Sepaase is a large protease of cysteine in eukaryotes and presents crucial roles in many cell processes, in particular chromosomal segregation during mitosis and meiosis, apoptosis, damage repair of DNA, from the disengagement of the centrosome and duplication, stabilization and elongation of the spindle. It dissolves the cohesion between sister chromatids by cleaving one of the subheadings of the cohesin ring for chromosome segregation. The sepaase activity is tightly controlled at several levels, by the direct binding of inhibitory proteins as well as the post-procedure modification. The dysregulation of SEARAISE business is related to cancer and genome instability, making it a drug discovery target. One of the most famous sepaase inhibitors is securin, which has been identified in yeast, plants and animals.
Securin forms a tight complex with sepaase and inhibits porceously its catalytic activity. The recent structures of the Sepase-Securin complex revealed the molecular mechanism of the safety inhibitor activity. A segment of securin is linked in the active sepaase site, thus blocking the substrate bonding. Securin itself is not cleaved by Separase because its link mode is not compatible with catalysis. Securin also has extensive interactions with sepaase outside the active site, according to its chaperone function to stabilize this enzyme. In several species, including Xenopus, the mouse and the man, two members of the Cyclin family have been identified. Cyclin A2, which is expressed ubiquitously in dividing cells and plays a role in the replication of DNA, entry into mitosis and the spindle assembly and cyclin A1, whose function is less clear and which is expressed in spermatocytes, leukemia cells and postmicathic multicile cells.
The suppression of the gene has shown that cyclin A1 is essential for masculine meiosis, but not essential for female meiosis. Our results revealed that the cyclin A1 is not only dispensable in the oocytes, we show here that its expression is actually undesirable in these cells. Our data demonstrate that CPA / C and oocyte proteasome are unable to target the cyclin A1 sufficiently prior to anchhase, which causes an arrest of anaphase and a direct inhibition of separation.
Separation of chromosomes during the masculine meiosis of Drosophila, I need a separate-mediated cleavage of the Uno homologous conjunction protein
Regular chromosomal segregation during the first meotic division requires a preliminary matching of homologous chromosomes in bivalent. During canonical meiosis, the bond between homologous chromosomes is maintained until the end of the metaphase I by chiasmata resulting from metiotic recombination in combination with a distal sister chromatide cohesion. Sepased removal of the cohesin of the chromosome arms at the end of the metaphase I allows the resolution of the chiasmata and the homologation to opposite spindle poles during an anaphase I. is interesting, sepaase is also required for The bivalent division during meiosis I in the males of Drosophila, where counterparts are jointly by an alternative mechanism independent of meiotic recombination and cohesin.
Here, we indicate the identification of a new alternative homologous conjunction protein encoded by previously increed genes uniforms only (UNO). Univalent in non-zero mutants at the beginning of meiosis I, instead of normal bivalents, are randomly separated. In the wild type, the UNO protein is detected in points associated with bivalent chromosomes and most abundantly at the localized twinning site of sexual chromosomes. Uno is cleaved by sepaase.
The expression of a single-mutant version with a non-functional sepaase cleavage site restores the counterpart of the homologous conjunction in a bottom of the UNO null. However, the separation of bivalent during meiosis, I am completely repealed by this unravelful version of the United Nations. Therefore, we propose that the homologous separation during the male meiosis of Drosophila is triggered by a separately-mediated divide of the UNO.
Centrosometive reduction of newly generated tetraploid cancer cells obtained by depletion of separation
Tetraploidy, a common characteristic of cancer, leads to the presence of additional centrosomes, associated with chromosomal instability (CIN) and aneuploidy. Deregulation in the number of centricsomes triggers tumorigenesis. However, how to evolve supernumerary centrics when the emergence of tetraploid cells remains elucidated. Here, generating tetraploid isogenic clones in colorectal cancer and in unprocessed cells, we show that almost tetraploid clones have a significant increase in the number of centricsomes. In addition, we find that the centrous region in quasi-tetraploids is twice as big as in the almost diploids. To assess whether the centrosome clustering would occur, we then analyzed the number of hundreds revealing the amplification of the hundred. Nevertheless, more than half of the quasi-tetraploids maintained in the culture do not have centrosomal aberrations. To determine if the cells have gradually lost the hundreds after becoming near tetraploids, we transfer transfected diploid cells with SIRNA against espl1 / separase, a protease responsible for triggering an anaphase, in order to generate newly tetraploid cells.
Finally, using this model, we evaluated the number of hundreds at different points of time after the tetrapolisation of the search for quasi-tetraploid rapidly losing centrosomes over time. Taken together, these data demonstrate that, although most cells reduce supernumerary centrosomes after tetrapolisation, a small fraction retains additional cottages, which potentially leads to CIN. The arrest of cyclin-induced cell cycle A1 is specific to the oocytes and the presence of cyclin A1 in early embryos has no effect on the progression of the cell cycle or the chromosomal division.
Description: A polyclonal antibody for detection of Separase from Human, Mouse. This Separase antibody is for WB, IHC-P, IF, ELISA. It is affinity-purified from rabbit antiserum by affinity-chromatography using epitope-specific immunogenand is unconjugated. The antibody is produced in rabbit by using as an immunogen synthesized peptide derived from human Separase around the non-phosphorylation site of S801
Description: A polyclonal antibody for detection of Separase from Human, Mouse. This Separase antibody is for WB, IHC-P, IF, ELISA. It is affinity-purified from rabbit antiserum by affinity-chromatography using epitope-specific immunogenand is unconjugated. The antibody is produced in rabbit by using as an immunogen synthesized peptide derived from human Separase around the non-phosphorylation site of S801
Description: A polyclonal antibody for detection of Separase from Human, Mouse. This Separase antibody is for WB, IHC-P, IF, ELISA. It is affinity-purified from rabbit antiserum by affinity-chromatography using epitope-specific immunogenand is unconjugated. The antibody is produced in rabbit by using as an immunogen synthesized peptide derived from human Separase around the non-phosphorylation site of S801
Description: Stable cohesion between sister chromatids before anaphase and their timely separation during anaphase are critical for chromosome inheritance. In vertebrates, sister chromatid cohesion is released in 2 steps via distinct mechanisms. The first step involves phosphorylation of STAG1 (MIM 604358) or STAG2 (MIM 300826) in the cohesin complex. The second step involves cleavage of the cohesin subunit SCC1 (RAD21; MIM 606462) by ESPL1, or separase, which initiates the final separation of sister chromatids.
Description: Stable cohesion between sister chromatids before anaphase and their timely separation during anaphase are critical for chromosome inheritance. In vertebrates, sister chromatid cohesion is released in 2 steps via distinct mechanisms. The first step involves phosphorylation of STAG1 (MIM 604358) or STAG2 (MIM 300826) in the cohesin complex. The second step involves cleavage of the cohesin subunit SCC1 (RAD21; MIM 606462) by ESPL1, or separase, which initiates the final separation of sister chromatids.
Description: Stable cohesion between sister chromatids before anaphase and their timely separation during anaphase are critical for chromosome inheritance. In vertebrates, sister chromatid cohesion is released in 2 steps via distinct mechanisms. The first step involves phosphorylation of STAG1 (MIM 604358) or STAG2 (MIM 300826) in the cohesin complex. The second step involves cleavage of the cohesin subunit SCC1 (RAD21; MIM 606462) by ESPL1, or separase, which initiates the final separation of sister chromatids.
Cyclin A1 is therefore not only a large cellular cycle regulator with germinal-biased expression, essential for men and damaging for female meiosis, persistent expression during anaphase in oocytes shows fundamental differences between APC / C in early ecytes and embryos.
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