Cell cycle regulation of a lympho-hematopoietic specific Rap1GTPase-activating protein, Spa-1 in lymphocyres.

我们克隆了小鼠Spa-1基因（Spa-1）的人同源基因（Spa-1），该基因编码一个130 kDa （p130）的与sh3结合的细胞质蛋白Rap1GAP。PEST和亮氨酸拉链/卷绕线圈领域。杆状病毒系统中表达的p130对Rap1具有特异性的gtpase激活活性。在NIH3T3细胞中，过表达截断的Spa-1cDNA明显干扰了g0阻滞的NIH3T3细胞在有丝分裂刺激后进入细胞周期，这表明该蛋白通过与Rap1的相互作用参与细胞周期调节。基因组图谱显示，Spa-1位于小鼠第19号染色体的着丝粒最集中的区域，在人类中位于假定的BCL1致癌基因CCND1/PRAD1的11q13.3的着丝粒附近。

We have cloned a human homologue of mouse Spa-1 gene (SPA-1) which encodes a 130 kDa (p130) cytoplasmic protein with SH3-binding, Rap1GAP.PEST and leucine zipper/coiled coil domains. p130 expressed in a Baculovirus system exhibits a specfic GTPase-activating activity against Rap1. Overexpression of a truncated Spa-1cDNA in NIH3T3 cells apparently disturbed the entry into the cell cycle in the G0-arrested NIH3T3 cells following mitogenic stimulation, suggesting that the protein is critically involved in the cell cycle regulation via the interaction with Rap1. Genomic mapping indicated that Spa-1 is located at the most centromeric region of chromosome 19 in mouse and at the centrimieric neighborhood of CCND1/PRAD1, a presumed BCL1 oncogene, at 11q13.3 in human.