Zhen M, Schein J E, Baillie D L, Candido E P
Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada.
EMBO J. 1996 Jul 1;15(13):3229-37.
The ubc-2 gene in Caenorhabditis elegans encodes a ubiquitin-conjugating enzyme (E2) homologous to yeast UBC4 and UBC5. UBC4 and UBC5 are individually dispensable class I E2 enzymes involved in the degradation of short-lived and abnormal proteins. Transgenic analysis using ubc-2-lacZ fusions and in situ immunofluorescence indicate that ubc-2 is abundantly expressed in most tissues of embryos and early larvae, but becomes specific to the nervous system in L4 larvae and adults. This suggests that the functions of this type of E2 are developmentally regulated in C.elegans. This hypothesis is supported by antisense analysis, which shows that blocking the expression of ubc-2 has a more severe effect in early developmental stages than in later stages. Through complementation of previously identified essential genes in the vicinity of ubc-2, we demonstrate that ubc-2 corresponds to let-70, a gene essential for C.elegans larval development. One let-70(ubc-2) allele contains a His75-->Tyr substitution, while another has an altered splice donor site.
秀丽隐杆线虫中的ubc - 2基因编码一种与酵母UBC4和UBC5同源的泛素结合酶（E2）。UBC4和UBC5分别是参与短命和异常蛋白质降解的I类E2酶，它们各自并非不可或缺。使用ubc - 2 - lacZ融合体的转基因分析和原位免疫荧光表明，ubc - 2在胚胎和早期幼虫的大多数组织中大量表达，但在L4幼虫和成虫中变得特异地表达于神经系统。这表明这种E2类型的功能在秀丽隐杆线虫中受到发育调控。反义分析支持了这一假设，该分析表明阻断ubc - 2的表达在早期发育阶段比在后期阶段具有更严重的影响。通过对ubc - 2附近先前鉴定的必需基因进行互补分析，我们证明ubc - 2对应于let - 70，这是一个对秀丽隐杆线虫幼虫发育至关重要的基因。一个let - 70(ubc - 2)等位基因含有一个His75→Tyr替换，而另一个具有改变的剪接供体位点。
