Analysis of a New Cell Cycle Gene Family in Drosophila and Sacaromyces

GCC（Growth & Cell Cycle，生长与细胞周期）-A1基因最初是在黑腹海蛞蝓中发现的，它是一种生长缓慢、体型缩小的突变体。发育不全的成虫鬃毛小，寿命短，雄性生殖力下降。由半形雌性产生的卵在卵裂期显示核分裂阻滞。双点分析显示，等位基因强度不同，克隆大小减小。这些结果表明它在细胞增殖或细胞生长中起作用。GCC-A1在眼内的过度表达以剂量依赖的方式产生粗眼表型。与细胞死亡基因的遗传相互作用表明，这种表面表型是由细胞凋亡引起的。过表达GCC-A1联合表达P35抑制细胞凋亡，导致小眼细胞数量增加。翼盘细胞过表达GCC-A1导致细胞大小增大，提示GCC-A1的主要作用可能是细胞生长。假定的gc - a1蛋白产物是新的，没有揭示其生化功能的基元，但数据库搜索发现秀丽隐杆线虫，酿酒酵母和pombe的未知功能基因共享同源性限制在大约150个氨基酸的结构域。我们破坏了酿酒葡萄球菌的4个基因，我们称之为GCC-A， -B1， -B2和-C。GCC- a干扰物在G1期被抑制，而GCC- c干扰物生长缓慢且不产孢，这表明GCC型蛋白在昆虫和酵母的细胞周期进程中都起作用。对标记蛋白的分析表明，果蝇和酵母的GCC- a都定位于细胞质的膜结构上，这进一步表明这些基因在两种生物中的作用相似。

The GCC(Growth ＆ Cell Cycle)-A1 gene was first identified in D. melanogaster as a mutant showing slow growth and reduced body size. Hypomorphic adults have small bristles, shortened lifespans and reduced male fertilty. Eggs produced by hypomorphic females show arrested nuclear divisions at cleavage stage. Twin-spot analysis revealed a reduction in clone size according to allelic strength. These results suggest a role in cell proliferation or cell growth. Over-expression of GCC-A1 in the eye produced a rough-eye phenotype in a dose dependent manner. Genetic interaction with cell death genes indicate this superficial phenotype is caused by apoptosis. Over-expression of GCC-A1 combined with expression of P35 to suppress apoptosis led to an increase in the number of ommatidia. Over-expression of GCC-A1 in the wing disc caused an increase in cell size, suggesting that GCC-A1's primary role may be in cell growth. GCC-A1's putative protein product is novel with no motifs revealing its biochemical function, but a database search found genes of unknown function in C. elegans, S. cerevisiae and S. pombe sharing homology restricted to a domain of approximately 150 amino acids. We disrupted the 4 genes in S. cerevisiae which we refer to as GCC-A, -B1, -B2 and -C. GCC-A disruptants are arrested at G1 phase and GCC-C disruptants show slow growth and do not sporulate suggesting that GCC type proteins function in cell cycle progression in both insects and yeast. Analysis of tagged proteins showed that both fly GCC and yeast GCC-A are localized at membrane structures in the cytoplasm suggesting further similarities in the roles of the genes in both organisms.