Yamaguchi Nobuyuki, Higa Mikihiko, Aiba Kazuhiro, Fang Hui, Tanaka Yoshimasa, Urushihara Hideko
Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki 305, Japan.
Dev Growth Differ. 1996 Jun;38(3):271-279. doi: 10.1046/j.1440-169X.1996.t01-2-00006.x.
The sexual cycle of the cellular slime mold, Dictyostelium discoideum, offers a suitable experimental system to analyze sexual cell interactions. We have been analyzing molecular mechanisms involved in sexual cell fusion using complementary heterothallic strains in D. discoideum and have identified several cell surface proteins involved in the process. One of them, gp138 is present in strains of both mating types and considered to be responsible for membrane fusion itself. Two genes with high mutual homology, GP138A and GP138B, have been identified so far as encoding this protein. Expression of antisense RNA for GP138B has been shown to suppress sexual cell fusion, confirming the critical importance of these genes in sexual cell fusion. However, neither the functional relationship of the two gp138 genes nor the possibility of the existence of more genes that encode gp138 has been determined yet. In the present study, GP138A and GP138B were disrupted by homologous recombination in an effort to clarify these points. Analysis of the double knock-out mutants suggested the presence of a third gene for gp138.
细胞黏菌盘基网柄菌的有性周期提供了一个合适的实验系统来分析有性细胞间的相互作用。我们一直在利用盘基网柄菌中的互补异宗配合菌株分析参与有性细胞融合的分子机制，并已鉴定出该过程中涉及的几种细胞表面蛋白。其中之一，gp138存在于两种交配型的菌株中，被认为负责膜融合本身。到目前为止，已鉴定出两个具有高度同源性的基因GP138A和GP138B编码该蛋白。已证明针对GP138B的反义RNA的表达可抑制有性细胞融合，证实了这些基因在有性细胞融合中的关键重要性。然而，两个gp138基因的功能关系以及是否存在更多编码gp138的基因的可能性尚未确定。在本研究中，为了阐明这些问题，通过同源重组破坏了GP138A和GP138B。对双敲除突变体的分析表明存在第三个gp138基因。
