Meiosis and small ubiquitin‐related modifier (SUMO)‐conjugating enzyme, Ubc9

Abstract

In this review, we describe the role of a small ubiquitin‐like protein modifier (SUMO)‐conjugating protein, Ubc9, in synaptonemal complex formation during meiosis in a basidiomycete, Coprinus cinereus. Because its meiotic cell cycle is long and naturally synchronous, it is suitable for molecular biological, biochemical and genetic studies of meiotic prophase events. In yeast two‐hybrid screening using the meiotic‐specific cDNA library of C. cinereus, we found that the meiotic RecA homolog CcLim15 interacted with CcUbc9, CcTopII and CcPCNA. Moreover, both TopII and PCNA homologs were known as Ubc9 interactors and the targets of sumoylation. Immunocytochemistry demonstrates that CcUbc9, CcTopII and CcPCNA localize with CcLim15 in meiotic nuclei during leptotene to zygotene when synaptonemal complex is formed and when homologous chromosomes pair. We discuss the relationships between Lim15/Dmc1 (CcLim15), TopII (CcTopII), PCNA (CcPCNA) and CcUbc9, and subsequently, the role of sumoylation in the stages. We speculate that CcLim15 and CcTopII work in cohesion between homologous chromatins initially and then, in the process of the zygotene events, CcUbc9 works with factors including CcLim15 and CcTopII as an inhibitor of ubiquitin‐mediated degradation and as a metabolic switch in the meiotic prophase cell cycle. After CcLim15–CcTopII dissociation, CcLim15 remains on the zygotene DNA and recruits CcUbc9, Rad54B, CcUbc9, Swi5‐Sfr1, CcUbc9 and then CcPCNA in rotation on the C‐terminus. Finally during zygotene, CcPCNA replaces CcLim15 on the DNA and the free‐CcLim15 is probably ubiquitinated and disappears. CcPCNA may recruit the polymerase. The idea that CcUbc9 intervenes in every step by protecting CcLim15 and by switching several factors at the C‐terminus of CcLim15 is likely. At the boundary of the zygotene and pachytene stages, CcPCNA would be sumoylated. CcUbc9 may also be involved with CcPCNA in the switch from the replicative polymerase being recruited at zygotene to the repair‐type DNA polymerases being recruited at pachytene.

Expression characteristics of the SUMOylation genes SUMO-1 and Ubc9 in the developing testis and ovary of Chinese mitten crab, Eriocheir sinensis

“…Cell division and gametogenesis are very active in the developing testis and ovary, where Ubc9 which regulates processes during meiosis and mitosis is expressed (Sakaguchi et al, 2007). Deficiency of Ubc9 in early post-implantation mouse embryos leaded to mitotic anomalies, including chromosome condensation and segregation defects (Vertegaal, 2007), and Ubc9 was involved in the development of mouse male germ cells (La Salle et al, 2008).…”

Coprinus cinereus Mer3 is required for synaptonemal complex formation during meiosis

“…Not only is its meiotic cell cycle long and naturally synchronous, but large populations of synchronous meiotic cells are also easy to obtain (Li et al 1999;Kües 2000;Kamada 2002;Casselton and Olesnicky 1998). These advantages have enabled us to isolate and characterize many synapsis-related proteins in C. cinereus (Nara et al 1999(Nara et al , 2001Hamada et al 2007;Ishizaki et al 2002;Namekawa et al 2003a, b, c;Yamaguchi et al 2004;Iwabata et al 2005;Koshiyama et al 2006;Sakamoto et al 2007;Sakaguchi et al 2007) and to demonstrate their roles in vivo.…”

SUMO-conjugating enzyme (Sce) and FK506-binding protein (FKBP) encoding rice (Oryza sativa L.) genes: genome-wide analysis, expression studies and evidence for their involvement in abiotic stress response

“…SUMO conjugation pathway is implicated in the activation of a chain of nuclear regulatory proteins whose activities may be needed at low levels in non-stressed and at high levels, in the stressed plants. The targets under negative regulation for instance include a battery of regulators that promote cell division (Sakaguchi et al 2007). Potential targets under positive regulation include heat shock factor (HSF) like proteins: HSF1 has been reported to undergo modiWcation at lysine298 by SUMO in HeLa cells (Hong et al 2001).…”