Microtubule nucleation: beyond the template
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4621832/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4621832/
PubMed Central (PMC)
Tissue patterning and cellular mechanics
In development, cells organize into biological tissues through cell growth, migration, and differentiation. Globally, this process is dictated by a genetically encoded program in which secreted morphogens and cell–cell interactions prompt the ...
11/1
Importin α Partitioning to the Plasma Membrane Regulates Intracellular Scaling (Cell 2019 Rebecca Heald UCB)
importin α: a conserved surface area-to-volume sensor that scales intracellular structures to cell size / a highly conserved and abundant nuclear transport factor that binds nuclear localization sequence (NLS)-containing proteins
palmitoylation-dependent importin α membrane association regulates mitotic spindle and nuclear scaling during Xenopus embryogenesis by providing a measure of the cell surface area-to-volume ratio
One technique - PEGylated surfactant
adding 2 μL of the extract reaction mixture on ice to 50 μL of the appropriate surfactant/lipid mixture
Cithrol DPHS resuspended in squalene at 50 mg/mL served as the surfactant to form inert membrane droplets, while total bovine liver extracts (preparation detailed above) were used as the physiological membrane surfactant
The extract/surfactant mixture was then pipetted up and down with a 20 μL pipette tip set to maximum volume approximately 10-20 times, depending on the desired size range of droplets desired.
The emulsified mixture was then added to a custom-built chamber composed of vacuum grease (Dow Corning) on a coverslip
Importin α Partitioning to the Plasma Membrane Regulates Intracellular Scaling (Cell 2019 Rebecca Heald UCB)
importin α: a conserved surface area-to-volume sensor that scales intracellular structures to cell size / a highly conserved and abundant nuclear transport factor that binds nuclear localization sequence (NLS)-containing proteins
palmitoylation-dependent importin α membrane association regulates mitotic spindle and nuclear scaling during Xenopus embryogenesis by providing a measure of the cell surface area-to-volume ratio
One technique - PEGylated surfactant
adding 2 μL of the extract reaction mixture on ice to 50 μL of the appropriate surfactant/lipid mixture
Cithrol DPHS resuspended in squalene at 50 mg/mL served as the surfactant to form inert membrane droplets, while total bovine liver extracts (preparation detailed above) were used as the physiological membrane surfactant
The extract/surfactant mixture was then pipetted up and down with a 20 μL pipette tip set to maximum volume approximately 10-20 times, depending on the desired size range of droplets desired.
The emulsified mixture was then added to a custom-built chamber composed of vacuum grease (Dow Corning) on a coverslip
11/2
Phenotypic plasticity and genetic control in colorectal cancer evolution (Nature 2022 British Andrea Sottoriva & Trevor A. Graham)
The article found a common phenomenon in CRC tumors (colorectal cancer), that tumors can acquire phenotypic plasticity without genetic factors (epigenetic or genetic) changes.
Phenotypic plasticity and genetic control in colorectal cancer evolution (Nature 2022 British Andrea Sottoriva & Trevor A. Graham)
The article found a common phenomenon in CRC tumors (colorectal cancer), that tumors can acquire phenotypic plasticity without genetic factors (epigenetic or genetic) changes.
11/2
The gut-to-brain axis for toxin-induced defensive responses (Cell 2022 北京生命科学研究所 曹鹏)
After food poisoning, the brain initiates a series of defense responses such as nausea and vomiting. Through vomiting, the human body excretes the ingested toxic food out of the digestive tract, preventing the pathogen from further invading the body.
Through the disgusting emotion of nausea, the brain can form a long-term memory of the characteristics of a poisonous food, so as to avoid eating the poisonous food again in the future.
Studying the "nausea-vomiting" response is difficult because rodents commonly used in the laboratory, such as mice and rats, do not exhibit vomiting behavior. Rodents are unable to spit food out of their stomachs, thought to be due to underdeveloped smooth muscles in the digestive tract
Past research has only been able to use animals that exhibit vomiting behavior, such as dogs and ferrets. They found that cutting the subphrenic vagus nerve can effectively block the vomiting response, indicating that vomiting depends on the "gut-to-brain" axis between the gastrointestinal tract and the brain.
Brain regions involved in the vomiting response identified by means of damage and electrical stimulation
Through pharmacological methods, it was found that antagonists of 5-HT3R and NK1R can effectively inhibit the emesis response
To elucidate the mechanism by which the brain initiates the "nausea-vomiting" response, in addition to appropriate animal models and research paradigms, three long-standing mysteries need to be solved.
First, after the gastrointestinal tract was invaded by pathogens, which type of intestinal cells gave this important information to the vagus nerve?
Second, what is the identity and characteristics of the sensory neurons in the vagus nerve responsible for interfacing with the gut "intelligence"?
Third, when the brain receives the information of pathogen invasion from the vagus nerve, how does it quickly and synchronously initiate a series of defense responses such as nausea and vomiting?
This study established a new paradigm for studying the "nausea-vomiting" response using mice as an animal model, and initially revealed the molecular, cellular and neural circuit mechanisms that trigger the "nausea-vomiting" response by the brain's perception of pathogen invasion.
The gut-to-brain axis for toxin-induced defensive responses (Cell 2022 北京生命科学研究所 曹鹏)
After food poisoning, the brain initiates a series of defense responses such as nausea and vomiting. Through vomiting, the human body excretes the ingested toxic food out of the digestive tract, preventing the pathogen from further invading the body.
Through the disgusting emotion of nausea, the brain can form a long-term memory of the characteristics of a poisonous food, so as to avoid eating the poisonous food again in the future.
Studying the "nausea-vomiting" response is difficult because rodents commonly used in the laboratory, such as mice and rats, do not exhibit vomiting behavior. Rodents are unable to spit food out of their stomachs, thought to be due to underdeveloped smooth muscles in the digestive tract
Past research has only been able to use animals that exhibit vomiting behavior, such as dogs and ferrets. They found that cutting the subphrenic vagus nerve can effectively block the vomiting response, indicating that vomiting depends on the "gut-to-brain" axis between the gastrointestinal tract and the brain.
Brain regions involved in the vomiting response identified by means of damage and electrical stimulation
Through pharmacological methods, it was found that antagonists of 5-HT3R and NK1R can effectively inhibit the emesis response
To elucidate the mechanism by which the brain initiates the "nausea-vomiting" response, in addition to appropriate animal models and research paradigms, three long-standing mysteries need to be solved.
First, after the gastrointestinal tract was invaded by pathogens, which type of intestinal cells gave this important information to the vagus nerve?
Second, what is the identity and characteristics of the sensory neurons in the vagus nerve responsible for interfacing with the gut "intelligence"?
Third, when the brain receives the information of pathogen invasion from the vagus nerve, how does it quickly and synchronously initiate a series of defense responses such as nausea and vomiting?
This study established a new paradigm for studying the "nausea-vomiting" response using mice as an animal model, and initially revealed the molecular, cellular and neural circuit mechanisms that trigger the "nausea-vomiting" response by the brain's perception of pathogen invasion.
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.pnas.org/doi/pdf/10.1073/pnas.2121147119
11/4
Emergent properties of mitotic chromosomes (Current Opinion in Cell Biology 2020 Rebecca Heald UCB)
How to connect the molecular-level activities to large-scale changes in whole-chromosome architecture that determine mitotic chromosome size, shape, and function.
In conclusion, multiple biochemical activities at the molecular level come together to mediate the large-scale chromosome organization and dynamics observed during mitosis.
Two major challenges:
integrating the many sources of structural information (imaging, sequencing, biochemistry) into a comprehensive, multiscale model for mitotic chromosome architecture
relating the structure and mechanics of mitotic chromosomes to their functions in cell division and epigenetic inheritance.
Emergent properties of mitotic chromosomes (Current Opinion in Cell Biology 2020 Rebecca Heald UCB)
How to connect the molecular-level activities to large-scale changes in whole-chromosome architecture that determine mitotic chromosome size, shape, and function.
In conclusion, multiple biochemical activities at the molecular level come together to mediate the large-scale chromosome organization and dynamics observed during mitosis.
Two major challenges:
integrating the many sources of structural information (imaging, sequencing, biochemistry) into a comprehensive, multiscale model for mitotic chromosome architecture
relating the structure and mechanics of mitotic chromosomes to their functions in cell division and epigenetic inheritance.
11/4
Rapid image deconvolution and multiview fusion for optical microscopy (Nature Biotechnology 2020)
Incorporating the image formation process into deep learning improves network performance (Nature Methods 2022)
Two optimization methods are proposed to improve the image resolution. One is to optimize the backprojection operator in the Richardson-Lucy deconvolution algorithm, which can improve the efficiency of deconvolution. The other is to use a deep learning network to learn the deconvolution mapping relationship.
In recent years, deep learning networks have performed well in various research fields, but its inexplicable "black box" characteristics and its high dependence on the quality of training data have led to the use of a content-based data training method. Models are difficult to apply directly to other types of data.
In this study, the Richardson-Lucy deconvolution model commonly used in post-processing of fluorescence microscopy images was explicitly introduced into the fully convolutional deep learning framework, and a Richardson-Lucy Network (RLN) was proposed to establish an iterative optimization method and a deep learning method. It can better realize the optimization of fluorescence microscopy image resolution, improve network interpretability and generalization ability, and build new intelligent modalities.
Rapid image deconvolution and multiview fusion for optical microscopy (Nature Biotechnology 2020)
Incorporating the image formation process into deep learning improves network performance (Nature Methods 2022)
Two optimization methods are proposed to improve the image resolution. One is to optimize the backprojection operator in the Richardson-Lucy deconvolution algorithm, which can improve the efficiency of deconvolution. The other is to use a deep learning network to learn the deconvolution mapping relationship.
In recent years, deep learning networks have performed well in various research fields, but its inexplicable "black box" characteristics and its high dependence on the quality of training data have led to the use of a content-based data training method. Models are difficult to apply directly to other types of data.
In this study, the Richardson-Lucy deconvolution model commonly used in post-processing of fluorescence microscopy images was explicitly introduced into the fully convolutional deep learning framework, and a Richardson-Lucy Network (RLN) was proposed to establish an iterative optimization method and a deep learning method. It can better realize the optimization of fluorescence microscopy image resolution, improve network interpretability and generalization ability, and build new intelligent modalities.
11/7
Blocking PD-L1–PD-1 improves senescence surveillance and ageing phenotype (Nature 2022 Makoto Nakanishi university of tokyo)
The researchers found that senescent cells heterogenously express the immune checkpoint PD-L1 (Programmed death-ligand 1), and PD-L1+ senescent cells accumulate in vivo with age.
This study demonstrates that eliminating PD-L1+ senescent cells by blocking PD-L1-PD-1 is a promising anti-aging therapeutic strategy.
Senescent hepatocytes induced by oncogenes and senescent stellate cells induced by injury could be eliminated by activated T cells and natural killer cells, respectively, suggesting a potential role of the immune system in the accumulation of senescent cells.
Blocking PD-L1–PD-1 improves senescence surveillance and ageing phenotype (Nature 2022 Makoto Nakanishi university of tokyo)
The researchers found that senescent cells heterogenously express the immune checkpoint PD-L1 (Programmed death-ligand 1), and PD-L1+ senescent cells accumulate in vivo with age.
This study demonstrates that eliminating PD-L1+ senescent cells by blocking PD-L1-PD-1 is a promising anti-aging therapeutic strategy.
Senescent hepatocytes induced by oncogenes and senescent stellate cells induced by injury could be eliminated by activated T cells and natural killer cells, respectively, suggesting a potential role of the immune system in the accumulation of senescent cells.
11/7
Histone H2B.8 compacts flowering plant sperm via chromatin phase separation (Nature 2022)
In eukaryotic cells, transposon-enriched heterochromatin is usually highly condensed, forming nuclear speckles and distributed at the edge of the nucleus, while gene-enriched euchromatin is loosely distributed in the nucleus and occupies nuclear space. This loosely distributed structure facilitates the binding of transcriptional complexes and promotes gene expression.
Condensed chromatin usually involves the repression of transcription, such as the condensed heterochromatin, which inhibits the activity of transposons and ensures the stability of the genome.
This paper discovers a novel mechanism for chromatin condensation that does not affect transcription. The authors discovered a histone H2B variant, H2B.8, expressed specifically in flowering plant sperm cells, which specifically binds to euchromatic transposons and intergenic regions. It condenses sperm cells by phase separation non-transcribed regions in the gene, thereby condensing sperm cell chromatin without affecting gene expression
This novel enrichment acts only on non-expressed euchromatin, thereby delicately reducing the size of the nucleus without affecting transcription.
Histone H2B.8 compacts flowering plant sperm via chromatin phase separation (Nature 2022)
In eukaryotic cells, transposon-enriched heterochromatin is usually highly condensed, forming nuclear speckles and distributed at the edge of the nucleus, while gene-enriched euchromatin is loosely distributed in the nucleus and occupies nuclear space. This loosely distributed structure facilitates the binding of transcriptional complexes and promotes gene expression.
Condensed chromatin usually involves the repression of transcription, such as the condensed heterochromatin, which inhibits the activity of transposons and ensures the stability of the genome.
This paper discovers a novel mechanism for chromatin condensation that does not affect transcription. The authors discovered a histone H2B variant, H2B.8, expressed specifically in flowering plant sperm cells, which specifically binds to euchromatic transposons and intergenic regions. It condenses sperm cells by phase separation non-transcribed regions in the gene, thereby condensing sperm cell chromatin without affecting gene expression
This novel enrichment acts only on non-expressed euchromatin, thereby delicately reducing the size of the nucleus without affecting transcription.
11/9
Disassembly of Actin and Keratin Networks by Aurora B Kinase at the Midplane of Cleaving Xenopus laevis Eggs (Current Biology 2019 Tim Mitchison)
Aurora B kinase activity between asters disassembles actin and keratin networks
Cytoskeleton disassembly results in reduced cytoplasmic stiffness between asters
Aurora B kinase bound to beads causes local disassembly of cytoskeleton networks
Microtubule binding locally amplifies Aurora B kinase activity
CPC - mitotic kinase Aurora B / three additional subunits (INCENP, Survivin, and Borealin) that localize and activate the kinase
Centralspindlin - kinesin-6, MKLP1, and two molecules of MgcRacGAP, which contains a GTPase-activating protein (GAP) domain for Rho family GTPases.
CPC - the boundary between asters.
Aurora B kinase (AURKB) (subunit of the CPC) - caused disassembly of F-actin and keratin between asters
cytokinesis signaling protein complexes: chromosomal passenger complex (CPC) and Centralspindlin
A requirement for CPC activity for cytokinesis was shown in several large cell types, including zebrafish [4], sea urchin [5], and Xenopus [6].
CPC is activated by auto-phosphorylation, which is enhanced by binding to microtubules [7]
a CPC-positive state from anaphase chromatin to the egg cortex is spread via microtubule bundles between asters [1][2]
F-actin and keratin networks - impede centrosome movement and furrow ingression
A plausible model is that CDK1 promotes global network disassembly at mitotic entry, whereas AURKB adds a focused disassembly activity that prevents re-formation at the midplane, which might impede furrow ingression.
CDK1
Actin-intact interphase egg extract containing fluorescent probes was spread between passivated coverslips and imaged.
AURKB and Prc1/Kif4A activities together block plus-end growth and generate sharp boundaries between asters, as previously reported [6, 19]
an AURKB kinase inhibitor - inhibit actin’s disassembly
Keratin networks were also disrupted at aster boundaries when CPC was recruited (slower than f-actin)
To examine these phenomena in vivo, we analyzed intact zygotes using fixation, clearing, and laser-scanning confocal imaging
The mechanism of local disassembly of F-actin by AURKB is not known.
How AURKB destabilizes keratin filaments is also unknown
Disassembly of Actin and Keratin Networks by Aurora B Kinase at the Midplane of Cleaving Xenopus laevis Eggs (Current Biology 2019 Tim Mitchison)
Aurora B kinase activity between asters disassembles actin and keratin networks
Cytoskeleton disassembly results in reduced cytoplasmic stiffness between asters
Aurora B kinase bound to beads causes local disassembly of cytoskeleton networks
Microtubule binding locally amplifies Aurora B kinase activity
CPC - mitotic kinase Aurora B / three additional subunits (INCENP, Survivin, and Borealin) that localize and activate the kinase
Centralspindlin - kinesin-6, MKLP1, and two molecules of MgcRacGAP, which contains a GTPase-activating protein (GAP) domain for Rho family GTPases.
CPC - the boundary between asters.
Aurora B kinase (AURKB) (subunit of the CPC) - caused disassembly of F-actin and keratin between asters
cytokinesis signaling protein complexes: chromosomal passenger complex (CPC) and Centralspindlin
A requirement for CPC activity for cytokinesis was shown in several large cell types, including zebrafish [4], sea urchin [5], and Xenopus [6].
CPC is activated by auto-phosphorylation, which is enhanced by binding to microtubules [7]
a CPC-positive state from anaphase chromatin to the egg cortex is spread via microtubule bundles between asters [1][2]
F-actin and keratin networks - impede centrosome movement and furrow ingression
A plausible model is that CDK1 promotes global network disassembly at mitotic entry, whereas AURKB adds a focused disassembly activity that prevents re-formation at the midplane, which might impede furrow ingression.
CDK1
Actin-intact interphase egg extract containing fluorescent probes was spread between passivated coverslips and imaged.
AURKB and Prc1/Kif4A activities together block plus-end growth and generate sharp boundaries between asters, as previously reported [6, 19]
an AURKB kinase inhibitor - inhibit actin’s disassembly
Keratin networks were also disrupted at aster boundaries when CPC was recruited (slower than f-actin)
To examine these phenomena in vivo, we analyzed intact zygotes using fixation, clearing, and laser-scanning confocal imaging
The mechanism of local disassembly of F-actin by AURKB is not known.
How AURKB destabilizes keratin filaments is also unknown
11/9
Spatial Organization of Cytokinesis Signaling Reconstituted in a Cell-Free System (Science 2014 Tim Mitchison)
The CPC was transported to overlap zones, which required two motor proteins, Kif4A and a Kif20A paralog.
cleavage furrow markers (including a RhoA-GTP reporter) was observed to be recruited to microtubule overlaps
the signaling complexes Centralspindlin and CPC (Chromosomal Passenger Complex) accumulate at the center of the midzone (or central spindle), which forms in the space previously occupied by the mitotic spindle
Where the expanding edges of two neighboring asters met, antiparallel microtubule bundles formed in a boundary zone that we term the aster-aster interaction zone (AAIZ)
CPC and Centralspindlin complexes are recruited to the midplane in anaphase - activate the small GTPase RhoA - to specify the division plane
CPC - is labeled by a GFP tagged DasraA subunit
CPC (AurkB) and the Kif23 subunit of Centralspindlin were recruited to the AAIZ
AAIZs in the cell-free system can signal to the cortex
The small GTPase RhoA is thought to be the master organizer of the furrow (16)
To localize active, GTP-bound RhoA we added an mCherry-tagged RhoA binding fragment of Rhotekin (mCherry-rGBD) (16).
the RhoA-GTP reporter was enriched at the bilayer under AAIZs that recruited CPC and Centralspindlin
a CPC-positive AAIZ can locally activate RhoA in our system
But we cannot distinguish whether localized AurkB phosphorylation of cytokinetic factors or some specific organization of microtubules at the AAIZ is required for furrow signaling.
Spatial Organization of Cytokinesis Signaling Reconstituted in a Cell-Free System (Science 2014 Tim Mitchison)
The CPC was transported to overlap zones, which required two motor proteins, Kif4A and a Kif20A paralog.
cleavage furrow markers (including a RhoA-GTP reporter) was observed to be recruited to microtubule overlaps
the signaling complexes Centralspindlin and CPC (Chromosomal Passenger Complex) accumulate at the center of the midzone (or central spindle), which forms in the space previously occupied by the mitotic spindle
Where the expanding edges of two neighboring asters met, antiparallel microtubule bundles formed in a boundary zone that we term the aster-aster interaction zone (AAIZ)
CPC and Centralspindlin complexes are recruited to the midplane in anaphase - activate the small GTPase RhoA - to specify the division plane
CPC - is labeled by a GFP tagged DasraA subunit
CPC (AurkB) and the Kif23 subunit of Centralspindlin were recruited to the AAIZ
AAIZs in the cell-free system can signal to the cortex
The small GTPase RhoA is thought to be the master organizer of the furrow (16)
To localize active, GTP-bound RhoA we added an mCherry-tagged RhoA binding fragment of Rhotekin (mCherry-rGBD) (16).
the RhoA-GTP reporter was enriched at the bilayer under AAIZs that recruited CPC and Centralspindlin
a CPC-positive AAIZ can locally activate RhoA in our system
But we cannot distinguish whether localized AurkB phosphorylation of cytokinetic factors or some specific organization of microtubules at the AAIZ is required for furrow signaling.
11/9
A microtubule-dependent zone of active RhoA during cleavage plane specification (JCB 2005 George von Dassow)
The small GTPase RhoA has previously been implicated in cytokinesis.
They observed that active RhoA concentrates in a precisely bounded zone before cytokinesis and is independent of actin assembly.
microtubules specify the cytokinetic apparatus via a dynamic zone of local RhoA activity.
A microtubule-dependent zone of active RhoA during cleavage plane specification (JCB 2005 George von Dassow)
The small GTPase RhoA has previously been implicated in cytokinesis.
They observed that active RhoA concentrates in a precisely bounded zone before cytokinesis and is independent of actin assembly.
microtubules specify the cytokinetic apparatus via a dynamic zone of local RhoA activity.
11/21
Rho GTPases in animal cell cytokinesis: An occupation by the one percent
Rho GTPases in animal cell cytokinesis: An occupation by the one percent
12/2
RNA-triggered protein cleavage and cell growth arrest by the type III-E CRISPR nuclease-protease
RNA-activated protein cleavage with a CRISPR-associated endopeptidas (Feng Zhang)
The Cas7-11–Csx29 effector is an RNA-dependent nuclease-protease system and is an important part of the bacterial anti-phage immune system. The system performs calculations at the post-translational protein level, so it has the potential to detect cancer cells and specific cell subtypes.
RNA-triggered protein cleavage and cell growth arrest by the type III-E CRISPR nuclease-protease
RNA-activated protein cleavage with a CRISPR-associated endopeptidas (Feng Zhang)
The Cas7-11–Csx29 effector is an RNA-dependent nuclease-protease system and is an important part of the bacterial anti-phage immune system. The system performs calculations at the post-translational protein level, so it has the potential to detect cancer cells and specific cell subtypes.
12/2
Structural basis for Cas9 off-target activity (Cell 2022 Switzerland Martin Jinek)
Cas9: complement guide CRISPR RNA (crRNA) by cleaving double-stranded DNA (dsDNA) substrates. In addition, by changing the sequence of the guide RNA (gRNA), the DNA-specific programming of the CRISPR-Cas9 system can also be easily realized.
This paper reports the crystal structure of Cas9 binding to a bona fide off-target substrate, revealing that off-target binding is achieved by a series of non-canonical base-pairing interactions in the heteroduplex directing the off-target
These studies provide a structural basis for the off-target activity of Cas9 and help improve the rational design of guide RNAs and off-target prediction algorithms.
Structural basis for Cas9 off-target activity (Cell 2022 Switzerland Martin Jinek)
Cas9: complement guide CRISPR RNA (crRNA) by cleaving double-stranded DNA (dsDNA) substrates. In addition, by changing the sequence of the guide RNA (gRNA), the DNA-specific programming of the CRISPR-Cas9 system can also be easily realized.
This paper reports the crystal structure of Cas9 binding to a bona fide off-target substrate, revealing that off-target binding is achieved by a series of non-canonical base-pairing interactions in the heteroduplex directing the off-target
These studies provide a structural basis for the off-target activity of Cas9 and help improve the rational design of guide RNAs and off-target prediction algorithms.
12/2
Refactored genetic codes enable bidirectional genetic isolation (Science 2022 Jason W. Chin Cambridge university)
Horizontal gene transfer (HGT): one way for evolution - The process of passing genetic material to other cells rather than progeny, such as conjugation, transduction, and transformation of cells
Gene vertical transfer: the process by which organisms pass genes to offspring.
This article reconstructs the genetic code structure of Escherichia coli and creates an orthogonal genetic code that limits the escape of synthetic genetic information into natural organisms.
A new codon rule was defined in which the TCG and TCA serine codons were replaced with the synonymous AGC and AGT codons, and the TAG stop codon was also replaced with TAA, resulting in the Syn61 strain - further improve it to Syn61∆3: Can barely read all codons in the universal genetic code
Refactored genetic codes enable bidirectional genetic isolation (Science 2022 Jason W. Chin Cambridge university)
Horizontal gene transfer (HGT): one way for evolution - The process of passing genetic material to other cells rather than progeny, such as conjugation, transduction, and transformation of cells
Gene vertical transfer: the process by which organisms pass genes to offspring.
This article reconstructs the genetic code structure of Escherichia coli and creates an orthogonal genetic code that limits the escape of synthetic genetic information into natural organisms.
A new codon rule was defined in which the TCG and TCA serine codons were replaced with the synonymous AGC and AGT codons, and the TAG stop codon was also replaced with TAA, resulting in the Syn61 strain - further improve it to Syn61∆3: Can barely read all codons in the universal genetic code
12/2
A cytokinesis furrow is positioned by two consecutive signals (Nature 2005 MPI)
Spindle midzone or aster - determine the cleavage furrow site
the cytokinesis furrow is first positioned by a signal determined by microtubule asters, and then by a second signal that is derived from the spindle midzone
A cytokinesis furrow is positioned by two consecutive signals (Nature 2005 MPI)
Spindle midzone or aster - determine the cleavage furrow site
the cytokinesis furrow is first positioned by a signal determined by microtubule asters, and then by a second signal that is derived from the spindle midzone
12/3
The incidence of cytoplasmic fragmentation in mouse embryos in vitro is not affected by inhibition of caspase activity (Fertility and sterility 2021 HKU)
Caspases are a family of endoproteases that provide critical links in cell regulatory networks controlling inflammation and cell death.
Caspases are a family of cytosolic aspartate-specific cysteine proteases involved in the initiation and execution of apoptosis
the formation of fragments in precompaction mouse embryos is independent of caspase activity and that embryo fragments are not apoptotic bodies.
The incidence of cytoplasmic fragmentation in mouse embryos in vitro is not affected by inhibition of caspase activity (Fertility and sterility 2021 HKU)
Caspases are a family of endoproteases that provide critical links in cell regulatory networks controlling inflammation and cell death.
Caspases are a family of cytosolic aspartate-specific cysteine proteases involved in the initiation and execution of apoptosis
the formation of fragments in precompaction mouse embryos is independent of caspase activity and that embryo fragments are not apoptotic bodies.