Chae S C, Inazu Y, Amagai A, Maeda Y
Biological Institute, Graduate School of Science, Tohoku University, Sendai, Aoba, 980-8578, Japan.
Biochem Biophys Res Commun. 1998 Nov 9;252(1):278-83. doi: 10.1006/bbrc.1998.9461.
In Dictyostelium discoideum Ax-2 cells, a specific point (PS-point) in the cell cycle from which they initiate differentiation in response to starvation has been specified. Using synchronized Ax-2 cells and the differential display method, a novel gene (differentiation-associated gene 2; dia2) was isolated as one of the genes expressed specifically during the shift of Ax-2 cells from growth to differentiation. The dia2 gene codes a lysine- and leucine-rich protein with a predicted molecular mass of 16.9 kDa. Northern blot analysis has shown that the dia2 mRNA, of 0.7 kb, accumulates in differentiating cells starved just before the PS-point, while there is no detectable expression in vegetatively growing cells. Antisense-mediated gene inactivation of dia2 greatly inhibited the progress of differentiation, presumably through the reduced expression of cAMP receptor 1 (car1). Thus, the DIA2 expression was suggested to have an essential role in the initiation of differentiation, closely relating to the cAMP signaling system.
在盘基网柄菌Ax-2细胞中，细胞周期中的一个特定点（PS点）已被确定，在饥饿刺激下，它们从该点开始分化。利用同步化的Ax-2细胞和差异显示方法，一个新基因（分化相关基因2；dia2）作为Ax-2细胞从生长转变为分化过程中特异性表达的基因之一被分离出来。dia2基因编码一种富含赖氨酸和亮氨酸的蛋白质，预测分子量为16.9 kDa。Northern印迹分析表明，0.7 kb的dia2 mRNA在刚好在PS点之前饥饿的分化细胞中积累，而在营养生长的细胞中没有可检测到的表达。反义介导的dia2基因失活极大地抑制了分化进程，推测是通过降低cAMP受体1（car1）的表达。因此，DIA2的表达被认为在分化起始中起关键作用，与cAMP信号系统密切相关。
