Hu L, Epstein L M, Roux K H
Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA.
Immunogenetics. 1997;46(4):267-75. doi: 10.1007/s002510050272.
We previously characterized the rabbit recombination activating gene-2 (RAG-2) coding region and a portion of the cDNA. Rabbit RAG-2 mRNA, however, was shown to be approximately twice as large as the predominant form expressed in other vertebrate species, suggesting that it contained additional coding and/or untranslated regions (UTR). In this report, we map and sequence the complete 5' and 3' UTRs of the rabbit RAG-2 transcript and identify and sequence the genomic regions from which they are transcribed. The data show that, with the exception of a 300 nucleotide 5' UTR, almost all of the additional sequence belongs to the 3' UTR and that the 3' UTR sequence is transcribed from a single large exon that encodes most of the coding region and all of the 3' UTR. The 3' UTR contains four poly A signal sites, the last of which is closely followed by a GU-rich region. The rabbit 3' UTR has a high level of identity with the homologous region downstream of the human RAG-2 gene but not with the mouse RAG-2 gene. The region of identity extends several hundred nucleotides beyond the transcribed region and terminates in a series of dinucleotide (TG) repeats. The data are discussed in terms of RAG gene and 3' UTR function, regulation, and evolution.
我们之前对兔重组激活基因-2（RAG-2）的编码区及部分cDNA进行了特征分析。然而，兔RAG-2 mRNA的大小约为其他脊椎动物物种中表达的主要形式的两倍，这表明它包含额外的编码区和/或非翻译区（UTR）。在本报告中，我们绘制了兔RAG-2转录本完整的5'和3'UTR图谱并进行测序，同时鉴定并测序了它们转录自的基因组区域。数据显示，除了一个300个核苷酸的5'UTR外，几乎所有额外的序列都属于3'UTR，并且3'UTR序列转录自一个单一的大外显子，该外显子编码大部分编码区和所有的3'UTR。3'UTR包含四个聚腺苷酸化信号位点，其中最后一个位点之后紧接着一个富含GU的区域。兔3'UTR与人RAG-2基因下游的同源区域具有高度的同一性，但与小鼠RAG-2基因的同源区域则不然。同一性区域在转录区域之外延伸数百个核苷酸，并在一系列二核苷酸（TG）重复处终止。我们从RAG基因以及3'UTR的功能、调控和进化方面对这些数据进行了讨论。
