One explanation for this unexpected finding is that, unlike Drosophila females, males do not undergo meiotic recombination and, therefore, arm cohesion is not essential to maintain chiasmata and ensure correct meiosis I segregation. These observations therefore suggest that the FPC is important for proper chromosome segregation in meiosis.
Protein concentration was determined using the Bradford method. On removal from liquid nitrogen, coverslips were removed and slides were placed in PBS. Relative Sgo1-GFP signal intensity was similar across genotypes. Circles of constant size were overlaid on undivided or divided nuclei to measure mean GFP intensity.
Replication origin selection regulates the distribution of meiotic recombination.
Our FISH analysis of sister-chromatid cohesion in wild-type spermatocytes agrees well with the results of Vazquez et al. In this work, we observed that the FPC components are required for proper cohesion dynamics. It is possible that many cohesinopathies van der Lelij et al. However, GFP fluorescence is significantly weaker than the signal we observe using GP43 antibodies, most likely because the ORD signal is amplified during the indirect immunodetection procedure.
Quantification of the level of GFP-ORD protein within individual nuclei from single fields of cells was performed on deconvolved volumes. Separase is required for chromosome segregation during meiosis I in Caenorhabditis elegans.
After each antibody incubation, slides were rinsed three times and washed for three 8-min periods in PBS. External link. Our cytological analysis of cohesion defects in prophase I ord null spermatocytes supports this conclusion.
ORD staining is absent in the somatically derived cyst cell arrow. Claspin, a novel protein required for the activation of Chk1 during a DNA replication checkpoint response in Xenopus egg extracts.
However, cleavage of centromeric cohesin subunits by the endopeptidase separase must be inhibited during meiosis I Klein et al. Replisome progression complex links DNA replication to sister chromatid cohesion in Xenopus egg extracts. A Live-cell images of meiotic cells carrying fluorescently tagged Cnp1 and Swi6.
In contrast to mitosis, wherein progenitor and daughter cells carry the same genetic information, meiosis produces daughters with half the number of parental chromosomes. To stain for ORD, squashes were incubated for 1.