Kim Y J, Baker B S
Department of Biological Sciences, Stanford University, California 94305.
J Neurosci. 1993 Mar;13(3):1045-56. doi: 10.1523/JNEUROSCI.13-03-01045.1993.
The rbp9 gene of Drosophila melanogaster has been molecularly characterized and shown to be expressed solely in the CNS, where it encodes proteins with three RNA recognition motifs (RRMs). Sequencing of genomic and cDNA clones of rbp9 revealed a complex gene with three alternative promoters as well as alternative patterns of splicing. The deduced amino acid sequence of the RBP9 proteins is highly similar to those of three other nervous system-specific genes, human HuC and HuD and Drosophila elav, which also encode proteins with three RRMs. Developmental Northern analysis revealed that rbp9 is expressed from the late third instar larva through adult stages. The RBP9 protein was detected specifically in nuclei of the nervous system after morphogenesis of the adult CNS in the mid-pupal stage. Thus, the RBP9 protein does not appear until substantially later than rbp9 transcripts are detected. The adult nervous system nuclear-limited expression pattern, the presence of RRMs, and the high similarity to a group of nervous system-specific proteins in flies and humans suggest that rbp9 belongs to a nervous system-specific RRM protein gene subfamily that may participate in the processing of RNAs involved in the development of the CNS.
黑腹果蝇的rbp9基因已进行了分子特征分析，结果表明它仅在中枢神经系统（CNS）中表达，在那里它编码具有三个RNA识别基序（RRMs）的蛋白质。rbp9的基因组和cDNA克隆测序显示，该基因很复杂，有三个可变启动子以及可变剪接模式。RBP9蛋白的推导氨基酸序列与其他三个神经系统特异性基因（人类的HuC和HuD以及果蝇的elav）的序列高度相似，后三者也编码具有三个RRMs的蛋白质。发育Northern分析表明，rbp9从三龄幼虫后期到成虫阶段均有表达。在蛹中期成虫中枢神经系统形态发生后，在神经系统的细胞核中特异性检测到了RBP9蛋白。因此，RBP9蛋白的出现明显晚于检测到rbp9转录本的时间。成虫神经系统细胞核受限的表达模式、RRMs的存在以及与果蝇和人类一组神经系统特异性蛋白质的高度相似性表明，rbp9属于一个神经系统特异性RRM蛋白基因亚家族，可能参与中枢神经系统发育过程中相关RNA的加工。
