一例性反转畸形SRY基因片段的扩增、克隆和核苷酸序列分析

在哺乳动物中，位于Ｙ染色体上的指导雄性性别分化的基因被命名为睾丸决定因子（Ｔｅｓｔｉｓ－ｄｅｔｅｒｍｉｎｉｎｇｆａｃｔｏｒ，ＴＤＦ）１９９０年６月分离获得的ＳＲＹ基因（Ｓｅｘ－ｄｅｔｅｒｍｉｎｉｎｇｒｅｇｉｏｎｏｆｔｈｅＹ）被认为是ＴＤＦ基因最好的候选者［１－４］。ＳＲＹ基因为单拷贝，位于Ｙ染色体短臂末端１Ａ１Ａ区，靠近假常染色体配对区（ＰＡＰＲ）的交界处，其部分顺序编码８０个保守性氨基酸组成的多肽。本实验使用与ＳＲＹ基因相应的引物，利用ＰＣＲ技术以一例性反转畸形病人的基因组ＤＮＡ为模板分离ＳＲＹ基因保守区顺序，并将特异扩增出的此ＳＲＹ基因片段重组到质粒ｐＵＣ１２中，得到含有ＳＲＹ基因片段的克隆。经测序表明其ＳＲＹ基因保守顺序上有Ｔ→Ｃ（Ｓｅｒ→Ｐｒｏ）突变。ＳＲＹ基因的存在及其突变可能是导致性反转畸形发病的原因。

Isolating,Clining and Sequencing of the SRY Gene in a Case of Sex Reversed Deformity

The gene which determines sexual differentiation located at Y chromosome in mammalian cell is mamed testis-determinting factor (TDF). The SRY gene seperated in June 1990 was regarded as the best candidate of TDF. SRY gene is a single copy gene coding a peptide containing 80 conserved amino acids. It is located at 1A1A of Y chromosome.closing to the conjunction of PAPR of pseudo-auto-chromoseome. We used PCR technique with primers complementary to SRY gene to amplify the SRY fragment from genomic DNA extracted from the peripheral blood of a sex reversed deformity patient.Then we cloned the SRY fragment into pUC12.The sequence analysis indicated that there was a point mutation from T→C(Ser→Pro) in the conserved sequence. The existence of SRY and the point mutation may be the cause of the sex reversed deformity.