The synaptonemal complex (SC), a meiosis-specific zipper-like tripartite structure, is constituted by the two parallel lateral elements (LEs) and the central elements (CEs). It is highly conserved among various eukaryotes. During meiotic prophase I, SC is considered as the structural framework in which homologous recombination occurs and genetic information rearrangement accomplishes. The identification of new SC components, companied with the precise understanding of SC would, therefore, be critically important for normal haploid gametes and accurate life cycle of sexual reproduction organisms.

 

A study team led by Prof. CHENG Zhukuan from the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, found that P31^comet is a new SC member in rice meiosis. P31^comet was characterized to participate in metaphase/anaphase transition during mitosis. This work, for the first time, provides experimental evidence for P31^comet function in meiosis.

 

In this study, P31^comet colocalizes with ZEP1 (a transverse filament protein of rice SC) to the central region between two axial elements (AEs) in an interpedently pattern. Further, P31^comet interacts with CENTRAL REGION COMPONENT 1 (CRC1, a SC component in rice) in yeast two-hybrid assays. Both suggest possible involvement of P31^comet in SC installation through its cooperation with CRC1. In addition, further investigation revealed that P31^comet is also essential for the programmed double-strand break initiation during rice meiosis. The abnormal chromosome fragmentation in Oscom1 and Osrad51c meiocytes was suppressed in both Oscom1 p31^comet and Osrad51c p31^comet, showing that P31^comet is a prerequisite for the double-strand break (DSB) repair.

 

This work entitled “P31^comet, a member of the synaptonemal complex, participates in meiotic DSB formation in rice” was online published in PNAS on September 6, 2016 (doi:10.1073/pnas.1607334113). It was supported by grants from the National Key Research and Development Program and National Natural Science Foundation of China.

 

 

 

 

Contact:

Dr. CHENG Zhukuan

E-mail: zkcheng@genetics.ac.cn