Koyama Y, Katagiri S, Hanai S, Uchida K, Miwa M
Department of Biochemistry and Molecular Oncology, Institute of Basic Medical Sciences and Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba 305-8575, Japan.
Gene. 1999 Jan 21;226(2):339-45. doi: 10.1016/s0378-1119(98)00529-0.
Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme that recognizes and binds to the nicks and ends of DNA, and catalyses successive ADP-ribosylation reactions. To clarify the function of PARP at the molecular level, we searched proteins which interact with PARP. In the auto-modification domain of PARP in Drosophila, there is a putative leucine-zipper motif which can interact with other protein molecules. To find interacting proteins we examined the auto-modification domain of Drosophila PARP, using the Far-Western screening method. From six independent cDNA clones isolated, we characterized two clones, PBP-3 and PBP-12. The predicted amino acid sequences from 109 to 269 of PBP-3 and from 184 to 312 of PBP-12 had more than 62% identities to mammalian L23a (rpl23a) and L22 (rpl22), the ribosomal proteins of the large subunit. This indicated that PBP-3 and PBP-12 are Drosophila homologues of L23a and L22, respectively. These Drosophila ribosomal protein L22 and L23a have additional Ala-, Lys- and Pro-rich sequences at the amino terminus, which have a resemblance to the carboxy-terminal portion of histone H1. Thus, Drosophila L22 and L23a might have two functions, namely the role of DNA-binding similar to histone H1 and the role of organizing the ribosome.
聚（ADP - 核糖）聚合酶（PARP）是一种核酶，它能识别并结合到DNA的切口和末端，并催化连续的ADP - 核糖基化反应。为了在分子水平上阐明PARP的功能，我们搜索了与PARP相互作用的蛋白质。在果蝇PARP的自身修饰结构域中，有一个推定的亮氨酸拉链基序，它可以与其他蛋白质分子相互作用。为了找到相互作用的蛋白质，我们使用Far - Western筛选方法检测了果蝇PARP的自身修饰结构域。从分离出的六个独立cDNA克隆中，我们鉴定了两个克隆，PBP - 3和PBP - 12。PBP - 3从109到269位的预测氨基酸序列以及PBP - 12从184到312位的预测氨基酸序列与哺乳动物大亚基核糖体蛋白L23a（rpl23a）和L22（rpl22）的同源性超过62%。这表明PBP - 3和PBP - 12分别是L23a和L22的果蝇同源物。这些果蝇核糖体蛋白L22和L23a在氨基末端有额外的富含丙氨酸、赖氨酸和脯氨酸的序列，这与组蛋白H1的羧基末端部分相似。因此，果蝇L22和L23a可能具有两种功能，即类似于组蛋白H1的DNA结合作用以及核糖体组装作用。
