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. 2011 Aug 5;30(18):3823–3829. doi: 10.1038/emboj.2011.263

Figure 1.

Figure 1

CKI-2Cip/Kip is repressed in germline stem cells. (A) CKI-1 and CKI-2 are C. elegans Cip/Kip proteins. Phylogenetic tree of Cip/Kip proteins obtained with ClustalW (default settings). Protein sequences were retrieved from Uniprot. (B) cki-2 is alternatively spliced. By 3′RACE analysis, cki-2 encodes two alternatively spliced mRNA isoforms, cki-2 L and S (1316 and 951 nt long, encoding a 259 and 175 amino acid-long protein, respectively). The ok2105 deletion removes most of the cki-2 coding sequence. (C) cki-2L mRNA predominates and is germline specific. Northern blot of cki-2 mRNA isolated from young (non-gravid) wild-type, glp-4 and cki-2(ok2105) mutants using a probe detecting both isoforms. cki-2L (black arrowhead, 1316 nt plus poly-A tail) predominates, while cki-2S (empty arrowhead, 951 nt+poly-A tail) is hardly detectable. cki-2 mRNA is absent from germline-less glp-4(bn2ts) animals and from ok2105 mutants. (D) CKI-2 protein is absent from germline stem cells. Immunodetection of CKI-2 in a dissected gonad (outlined). CKI-2 is expressed upon meiotic entry but not in the distal-most stem cells, which are here and in the remaining figures marked by an asterisk. Scale bar: 50 μm.