The Drosophila pumilio gene: an unusually long transcription unit and an unusual protein.
The Drosophila pumilio gene: an unusually long transcription unit and an unusual protein.
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作者：
Paul M. Macdonald
果蝇后体平面的特化需要一个预先定位在胚胎后极的决定子的作用。在胚胎发生过程中，这一决定因素似乎向前移动的过程依赖于pumilio（pum）基因。本文报道了果蝇pum基因cDNA的克隆和分子鉴定，以及pum mRNA和蛋白在果蝇早期发育过程中的表达分析。pum基因异常大;基因组和cDNA序列的比较显示，pum转录单位的长度至少为160 kb。pum cDNA编码一个157 × 10（3）M（r）蛋白，主要由富含单一氨基酸的区域组成，通常是甘氨酸、丙氨酸、谷氨酰胺或丝氨酸/苏氨酸。还存在36个氨基酸重复单元的6个串联重复。Pum蛋白质是细胞质的，并且集中在胚胎的皮层下区域。pum蛋白的分布沿胚胎前后轴没有沿着不对称性。
Specification of the posterior body plan in Drosophila requires the action of a determinant prelocalized to the posterior pole of the embryo. During embryogenesis this determinant appears to move anteriorly in a process dependent on the pumilio (pum) gene. This report describes the cloning and molecular characterization of a cDNA derived from the pum gene, and the analysis of pum mRNA and protein expression during early Drosophila development. The pum gene is unusually large; comparison of genomic and cDNA sequences reveals that the pum transcription unit is at least 160 kb in length. The pum cDNA encodes a 157 x 10(3) M(r) protein which consists mainly of regions enriched in a single amino acid, usually glycine, alanine, glutamine or serine/threonine. Six tandem repeats of a 36 amino acid repeat unit are also present. Pum protein is cytoplasmic and is concentrated in a subcortical region of the embryo. The distribution of pum protein exhibits no asymmetry along the anteroposterior axis of the embryo.