413회 Distinctive roles of four CDC25 family members during germline de…

413회 (2008. 4. 3.)

연사 : 심 용 희 교수, 건국대학교 특성화학부 생명공학과 부교수

제목 : Distinctive roles of four CDC25 family members during germline development in C. elegans

Abstract

For the cell cycle regulator, CDC25, there are four C. elegans homologs, CDC-25.1 to CDC-25.4.  CDC-25.1 is known as an important key player during G1/S transition.  It is maternally loaded into embryos and consequently essential for embryogenesis.  In addition, post-embryonically, it functions exclusively in germline development as deletion allele of cdc-25.1, nr2036, was previously reported to exhibit sterility due to defective germ cell proliferation while somatic post-embryonic development was not affected.  These results suggest that CDC-25.1 is essential for germline development and other family members of CDC25 may be responsible for somatic cell divisions. To investigate these possibilities we examined functions of CDC-25.1, 2, 3, and 4 by characterizing its mutant and RNAi phenocopies.  cdc-25.2, cdc-25.3 mutant alleles showed sterility, in which germ cell proliferation occurred unlike cdc-25.1 but germ cell differentiation was defective.  RNAi of cdc-25.4 showed similar phenocopy.  These results indicate that all four CDC-25 family members of C. elegans are required for germline development with distinctive roles of each member but not for the post-embryonic soma development.  Analysis for expression levels of four cdc-25 mRNA supported this hypothesis as their levels are dependent on the number of germ cells, oocytes and sperm, respectively.  Further study showed that CDC-25 family members are interacting with WEE-1.3 during the germline development.  We obtained some genetic data suggesting that CDC-25 family members and WEE-1.3 may coordinately regulate germline development at several different steps.