King C R, Piatigorsky J
Cell. 1983 Mar;32(3):707-12. doi: 10.1016/0092-8674(83)90056-9.
The eye lens contains a structural protein (alpha-crystallin), composed of two homologous primary gene products, alpha A2 and alpha B2. In certain rodents, there is another minor alpha-crystallin polypeptide, alpha Ains, which is identical to alpha A2 except for a 22 amino acid insert between residues 63 and 64 of the alpha A2 chain. Here we show that the mouse contains a single alpha A-crystallin gene, which has a 1376 bp intron separating codons 63 and 64 of the alpha A2-crystallin mRNA. A sequence encoding a 23 amino acid insert peptide was found 266 bp into the intron. The nucleotide borders of this sequence deviate from the AGGT consensus sequence. The DNA sequence encoding the insert peptide hybridizes to a cytoplasmic 14S RNA, demonstrating that it is transcribed in the lens. We propose that the murine alpha A2-crystallin gene generates both the alpha A2 and the alpha Ains mRNAs by alternative splicing.
晶状体包含一种结构蛋白（α-晶体蛋白），它由两种同源的初级基因产物αA2和αB2组成。在某些啮齿动物中，还有另一种次要的α-晶体蛋白多肽αAins，它与αA2完全相同，只是在αA2链的第63和64位残基之间有一个22个氨基酸的插入序列。在此我们表明，小鼠含有一个单一的αA-晶体蛋白基因，该基因有一个1376 bp的内含子，将αA2-晶体蛋白mRNA的第63和64个密码子隔开。在该内含子中266 bp处发现了一个编码23个氨基酸插入肽的序列。该序列的核苷酸边界偏离了AGGT共有序列。编码插入肽的DNA序列与细胞质中的14S RNA杂交，表明它在晶状体中被转录。我们提出，小鼠αA2-晶体蛋白基因通过可变剪接产生αA2和αAins两种mRNA。
