Myers S M, Eng C, Ponder B A, Mulligan L M
Department of Pathology, Queen's University, Kingston, ON, Canada.
Oncogene. 1995 Nov 16;11(10):2039-45.
The RET proto-oncogene, which encodes a receptor tyrosine kinase, displays multiple alternative splicing variants. Splicing of sequences 3' of exon 19 to generate several coding and untranslated region (UTR) sequences has been previously reported. We have sequenced the full length RET coding region and characterized the transcripts and 3' UTRs generated by alternative splicing of the RET 3' terminus. These analyses were performed using both RET cDNA cloned from a pheochromocytoma library and reverse transcriptase PCR products generated using RNA from a neuroblastoma cell line (LA-N-2). Three different carboxyl termini were identified. In addition to the nine and 51 terminal amino acid forms already known, we identified a third with 43 terminal amino acids predicted to encode a novel RET protein isoform. A total of 3621 base pairs of DNA 3' of exon 19, which spans the alternatively spliced exons and RET UTRs, was sequenced. Four polyadenylation sites were identified. The observed combinations of polyadenylation sites and 3' coding sequence suggest that RET transcripts with up to 10 different 3' sequences and up to 40 different full length RET transcripts may exist.
编码受体酪氨酸激酶的RET原癌基因存在多种可变剪接变体。此前已有报道外显子19下游序列的剪接可产生多个编码序列和非翻译区（UTR）序列。我们对RET编码区全长进行了测序，并对RET 3'末端可变剪接产生的转录本和3'UTR进行了表征。这些分析使用了从嗜铬细胞瘤文库克隆的RET cDNA以及用神经母细胞瘤细胞系（LA-N-2）的RNA生成的逆转录酶PCR产物。鉴定出了三种不同的羧基末端。除了已知的九和51个末端氨基酸形式外，我们还鉴定出了第三种，其具有43个末端氨基酸，预计可编码一种新的RET蛋白异构体。对跨越可变剪接外显子和RET UTR的外显子19下游3621个碱基对的DNA进行了测序。鉴定出了四个聚腺苷酸化位点。观察到的聚腺苷酸化位点和3'编码序列的组合表明，可能存在多达10种不同3'序列和多达40种不同全长RET转录本的RET转录本。
