High impact information on REC8

• In yeast, resolution of chiasmata in meiosis I requires proteolytic cleavage along chromosome arms of cohesin's Rec8 subunit by separase [1].
• This prevents removal of Rec8 from chromosome arms and resolution of chiasmata [1].
• We also show that the meiosis-specific cohesin, Rec8, is essential for maintaining cohesion between sister centromeres but not for monopolar attachment [2].
• We show here that cleavage of Rec8 by separin at one of two different sites is necessary for the resolution of chiasmata and the disjunction of homologous chromosomes during meiosis [3].
• Between metaphase I and metaphase II, REC-8 is partially lost from the chromosomes [4].

Biological context of REC8

• Deletion of the REC8 gene increases S-phase length, by approximately 10% in wild-type and approximately 30% in a spo11Delta background [5].
• However, in contrast to other Shugoshins, we observed an early and REC8-dependent recruitment of ZmSGO1 in maize, suggesting that control of SGO1 recruitment to chromosomes is different in plants than in other model organisms [6].
• One group of proteins that is essential for sister chromatid cohesion during mitosis and meiosis is the RAD21/REC8 family of cohesin proteins [7].
• Meiotic cohesin serves in sister chromatid linkage and DNA repair until its subunit Rec8 is cleaved by separase [8].
• Roles for Rec8 and/or Spo11 in progression through other stages of meiosis are also revealed [5].

Anatomical context of REC8

• Proteolytic cleavage, presumably of Rec8, might be a common trigger for the first meiotic division in eukaryotic cells [9].
• Analysis of meiosis in Rec8(mei8)/Rec8(mei8) spermatocytes showed that, while initiation of recombination and synapsis occurs, REC8 is required for the completion and/or maintenance of synapsis, cohesion of sister chromatids, and the formation of chiasmata, as it is in other organisms [10].
• Spermatids expressed rad21 and rec8 mRNAs simultaneously [11].
• We investigate here the mRNA expression patterns of mouse homologues of the yeast mitotic cohesin rad21 and the meiotic cohesin rec8 in various organs, with special attention to their expression in gonads [11].
• In the ovary, rad21 mRNA was detected in all of the ovarian cells including germ cells and somatic cells, whereas rec8 mRNA was detected only in oocytes [11].

Associations of REC8 with chemical compounds

• Disjunction of homologous chromosomes in meiosis I depends on proteolytic cleavage of the meiotic cohesin Rec8 by separin [3].

Physical interactions of REC8

• Meiotic cohesin REC8 marks the axial elements of rat synaptonemal complexes before cohesins SMC1beta and SMC3 [12].

Regulatory relationships of REC8

• The Spo12 and Slk19 proteins have been implicated in regulating meiosis I kinetochore orientation and/or in preventing cleavage of Rec8 at centromeres [13].

Other interactions of REC8

• The presence of Rec8, Red1, or Hop1 renders Mnd1 indispensable for DNA repair, presumably through the establishment of interhomolog (IH) bias [14].
• The loading of Pds5p onto chromosome requires the function of REC8, but the association of Rec8p with chromosome is independent of PDS5 [15].
• Proteolytic cleavage of cohesin's Rec8 subunit by separase destroys cohesion between sister chromatid arms at anaphase I and thereby resolves chiasmata [13].
• C(2)M associates in vivo with the Smc3 cohesin subunit, as previously shown for yeast Rec8 [16].

Analytical, diagnostic and therapeutic context of REC8

• In immunoblotting and immunohistochemical analysis using specific antibodies against mouse Rec8, we found that Rec8 was expressed in the testis but not in the kidney or liver; more precisely, it was expressed in spermatocytes and spermatids but not in spermatogonia or other somatic cells [17].
• We conducted in situ hybridization analysis to identify the cells that express rad21 and rec8 mRNAs in the gonads [11].
• Northern blot and reverse transcription-polymerase chain reaction (RT-PCR) analyses revealed that, in contrast to the ubiquitous expression of rad21 mRNA in all of the organs examined, rec8 was expressed only in the gonads [11].

References