Fujita Atsushi, Lord Matthew, Hiroko Takatoshi, Hiroko Fumika, Chen Tracy, Oka Chitoshi, Misumi Yoshio, Chant John
National Institute of Advanced Industrial Science and Technology, Tsukuba Central 6-4, 1-1 Higashi, Tsukuba 305-8566, Japan.
Gene. 2004 Mar 3;327(2):161-9. doi: 10.1016/j.gene.2003.11.021.
In Saccharomyces cerevisiae, cell type determines two distinct spatial budding patterns. Haploid cells exhibit an axial pattern, whereas diploid cells exhibit a bipolar pattern. Axl1, a member of the insulin-degrading enzyme (IDE) family, is the key morphological determinant for the haploid axial pattern. Here we identified a novel gene, RAX1, specifically required for the bipolar budding pattern. Loss of RAX1 alters the bipolar pattern of axl1 haploids resulting in reversion to the axial pattern, and also alters the bipolar patterns of bud3 and bud4 haploids. However, bud10 rax1 haploids exhibit a random budding pattern, suggesting Bud10 acts as the key proximal landmark in axial budding. Rax1 is required for the localization of Bud8, the distal bipolar budding landmark. Interestingly, Rax1 contains a C-terminal domain possessing some similarity to insulin-related peptides. Our results suggest that Rax1 is necessary for the establishment of the bipolar budding landmark.
在酿酒酵母中，细胞类型决定了两种不同的空间出芽模式。单倍体细胞呈现轴向模式，而二倍体细胞呈现双极模式。Axl1是胰岛素降解酶（IDE）家族的成员，是单倍体轴向模式的关键形态决定因素。在这里，我们鉴定了一个新基因RAX1，它是双极出芽模式所特需的。RAX1的缺失改变了axl1单倍体的双极模式，导致其恢复为轴向模式，同时也改变了bud3和bud4单倍体的双极模式。然而，bud10 rax1单倍体呈现随机出芽模式，这表明Bud10在轴向出芽中作为关键的近端标记物。Rax1是远端双极出芽标记物Bud8定位所必需的。有趣的是，Rax1包含一个与胰岛素相关肽有一定相似性的C末端结构域。我们的结果表明，Rax1对于双极出芽标记物的建立是必需的。
