牛α-s1酪蛋白基因5’端及上游区的克隆鉴定和部分序列分析

Cloning, Characterization and Partial Sequence of Bovine α-s1 Casein Gene

本文以PCR法克隆得到牛α-sl酪蛋白基因5'端800bp片段,并以该片段为探针,筛选了以EMBL3为载体构建的牛基因组文库,得到一个阳性克隆。酶切该克隆,并以牛α-s1酪蛋白基因5'端800bp片段及该基因cDNA为探针杂交,鉴定了该插入片段的方向,亚克隆了各相应酶切片段,制作了较为详细的限制酶图谱,并分析了该基因转录起始点前后部分序列。与该基因现有的资料比较,酶切图谱存在部分位点的差异,序列存在少量突变和缺失,在5'上游区均发现有内含子及外显子部分,且缺失均发生于有重复序列的部位。

We have isolated a clone from a bovine genomic library in EMBL3 using the probe with 5' portion including-660 to 158 bp of the bovine α-s1 casein gene obtained by PCR. Hybridization assays with probes of both the full length cDNA and 5' flanking fragment of α-s1 casein gene, restriction enzyme mapping and partial sequence analysis indicated that the fragment cloned spans 5.7kb of the first part of the gene and 8kb of its upstream flanking region, and has some divergence in restriction enzyme map compared with the published, and has a few mutations, deletionsamong the gene cloned, the PCR-generated fragment and the published sequence in either exon, or intron or flanking region, and all the deletions occurs at the sites of repeat sequence.