Amero S A, Matunis M J, Matunis E L, Hockensmith J W, Raychaudhuri G, Beyer A L
Department of Molecular and Cellular Biochemistry, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153.
Mol Cell Biol. 1993 Sep;13(9):5323-30. doi: 10.1128/mcb.13.9.5323-5330.1993.
The protein on ecdysone puffs (PEP) is associated preferentially with active ecdysone-inducible puffs on Drosophila polytene chromosomes and contains sequence motifs characteristic of transcription factors and RNA-binding proteins (S. A. Amero, S. C. R. Elgin, and A. L. Beyer, Genes Dev. 5:188-200, 1991). PEP is associated with RNA in vivo, as demonstrated here by the sensitivity of PEP-specific chromosomal immunostaining in situ to RNase digestion and by the immunopurification of PEP in Drosophila cell extract with heterogeneous nuclear ribonucleoprotein (hnRNP) complexes. As revealed by sequential immunostaining, PEP is found on a subset of chromosomal sites bound by the HRB (heterogeneous nuclear RNA-binding) proteins, which are basic Drosophila hnRNPs. These observations lead us to suggest that a unique, PEP-containing hnRNP complex assembles preferentially on the transcripts of ecdysone-regulated genes in Drosophila melanogaster presumably to expedite the transcription and/or processing of these transcripts.
蜕皮激素胀泡蛋白（PEP）优先与果蝇多线染色体上活跃的蜕皮激素诱导胀泡相关联，并且含有转录因子和RNA结合蛋白的特征性序列基序（S.A.阿梅罗、S.C.R.埃尔金和A.L.拜尔，《基因与发育》5:188 - 200，1991）。PEP在体内与RNA相关联，此处通过原位PEP特异性染色体免疫染色对核糖核酸酶消化的敏感性以及用异质性核核糖核蛋白（hnRNP）复合物在果蝇细胞提取物中免疫纯化PEP得以证明。通过连续免疫染色发现，PEP存在于由HRB（异质性核RNA结合）蛋白结合的染色体位点的一个子集中，HRB蛋白是果蝇的碱性hnRNP。这些观察结果使我们推测，一种独特的、含有PEP的hnRNP复合物优先组装在黑腹果蝇中蜕皮激素调节基因的转录本上，大概是为了加速这些转录本的转录和/或加工。
