Garel A, Nony P, Prudhomme J C
Université Claude Bernard, Lyon 1, Centre de Génétique Moléculaire et Cellulaire, UMR 106, Villeurbanne, France.
Genetica. 1994;93(1-3):125-37. doi: 10.1007/BF01435245.
Mag is a retrotransposon found as an insert in the Sericin 2 gene. It is present in a few copies--4 to 15--dispersed in the genome of different strains of Bombyx mori as well as in Bombyx mandarina. Flanked by a 5 bp target sequence with no sequence specificity, it is bordered by direct repeats of 77 nucleotides. Despite their unusual short size, these terminal repeats and their immediately adjacent sequences present all the signals necessary for transcription into genomic RNA and for reverse transcription. Mag contains two overlapping open reading frames which are organized as the gag and pol genes of retroviruses and encode putative nucleic acid binding peptide, protease, reverse transcriptase, RNase H and endonuclease in this order. Sequence comparison of these proteins places mag within the gypsy group of LTR retrotransposons next to the echinoderm element SURL.
Mag是一种逆转录转座子，作为插入序列存在于丝胶蛋白2基因中。它以4到15个拷贝的形式存在，分散在不同家蚕品系以及野桑蚕的基因组中。它两侧是一个没有序列特异性的5bp靶序列，边界是77个核苷酸的正向重复序列。尽管这些末端重复序列及其紧邻序列异常短小，但它们呈现出转录为基因组RNA和逆转录所需的所有信号。Mag包含两个重叠的开放阅读框，其组织方式与逆转录病毒的gag和pol基因相同，并依次编码假定的核酸结合肽、蛋白酶、逆转录酶、RNase H和内切核酸酶。这些蛋白质的序列比较将mag置于LTR逆转录转座子的吉普赛组中，紧挨着棘皮动物元件SURL。
