Multiple mRNA isoforms of the transcription activator protein CREB: generation by alternative splicing and specific expression in primary spermatocytes.
Multiple mRNA isoforms of the transcription activator protein CREB: generation by alternative splicing and specific expression in primary spermatocytes.
复制标题
转录激活蛋白 CREB 的多种 mRNA 亚型：通过选择性剪接产生并在初级精母细胞中特异性表达。
作者：
S. Ruppert;Tim J. Cole;M. Boshart;E. Schmid;G. Schütz
我们已经鉴定了代表小鼠CREB（环AMP响应元件结合蛋白）mRNA亚型的cDNA克隆。这些包括CREB δ和CREB α，它们的大鼠和人类同源物先前已被确定。两者都编码具有CRE结合活性和相同的转激活电位的蛋白质。额外的CREB mRNA亚型可能编码CREB相关蛋白。从小鼠CREB基因的结构组织我们得出结论，多个转录本是由选择性剪接产生的。此外，我们发现特定的CREB mRNA亚型在成年睾丸中高水平表达。这些同工异构体的表达在精子发生开始后被诱导。原位杂交表明这种表达主要发生在原代精母细胞中。CREB基因与最近分离的cAMP响应元件调节剂（CREM） cdna的比较表明，这两个基因是由基因复制产生的，并分化为编码cAMP信号转导途径的转录激活因子和抑制因子。
We have characterized cDNA clones representing mouse CREB (cyclic AMP responsive element binding protein) mRNA isoforms. These include CREB delta and CREB alpha, of which the rat and human homologues have been previously identified. Both encode proteins with CRE‐binding activity and identical transactivation potential. The additional CREB mRNA isoforms potentially encode CREB related proteins. From the structural organization of the mouse CREB gene we conclude that the multiple transcripts are generated by alternative splicing. Furthermore we show that specific CREB mRNA isoforms are expressed at a high level in the adult testis. Expression of these isoforms is induced after commencement of spermatogenesis. In situ hybridization suggests that this expression occurs predominantly in the primary spermatocytes. Comparison of the CREB gene with the recently isolated CREM (cAMP responsive element modulator) cDNAs illustrates that the two genes have arisen by gene duplication and have diverged to encode transcriptional activators and repressors of the cAMP signal transduction pathway.