Rodakis G C, Lecanidou R
Department of Biochemistry, Cell and Molecular Biology and Genetics, University of Athens, Panepistimiopolis, Greece.
J Mol Evol. 1992 Apr;34(4):315-23. doi: 10.1007/BF00160238.
Three beta-type early chorion gene copies (6F6.1, 6F6.2, and 6F6.3) are dispersed in the late region of chorion locus Ch1-2. Detailed analysis of the 5'-flanking region and the intron of 6F6.1 shows that they contain sequences that are homologous to Bombyx mori Bm1 repeat elements. Interestingly, the Bm1-type segment of the intron is interrupted by the insertion of a sequence that shows significant similarities with part of an intron of B. mori and Bombyx mandarina fibroin genes, and with part of the 3'-flanking region of B. mori prothoracicotropic hormone and tRNA-Glu genes; this sequence may represent a new repetitive, possibly transposable, element of B. mori. Following the Bm1-homologous sequence of the 6F6.1 5'-flanking region and preceding the gene promoter region, a short DNA segment shows sequence motifs that are also present in the ErA.1 promoter region. The occurrence of these sequences near one end or within the Bm1 repeat element is suggestive of complex sequence transfer events. Comparative analysis of known B. mori chorion alpha-gene promoters and of Bm1 repeat elements suggests, with marginal statistical significance, that these two sets of sequences contain common elements.
三个β型早期绒毛膜基因拷贝(6F6.1、6F6.2和6F6.3)分散在绒毛膜基因座Ch1-2的晚期区域。对6F6.1的5'侧翼区域和内含子的详细分析表明,它们包含与家蚕Bm1重复元件同源的序列。有趣的是,内含子的Bm1型片段被一个序列插入打断,该序列与家蚕和野桑蚕丝心蛋白基因的一个内含子部分、家蚕促前胸腺激素和tRNA-Glu基因的3'侧翼区域部分具有显著相似性;该序列可能代表家蚕的一种新的重复元件,可能是可转座元件。在6F6.1 5'侧翼区域的Bm1同源序列之后且在基因启动子区域之前,一个短DNA片段显示出也存在于ErA.1启动子区域的序列基序。这些序列在Bm1重复元件一端附近或内部的出现暗示了复杂的序列转移事件。对已知的家蚕绒毛膜α基因启动子和Bm1重复元件的比较分析表明,这两组序列含有共同元件,不过统计学意义不大。