Plant E P, Goodwin T J, Poulter R T
Department of Biochemistry, University of Otago, Dunedin, New Zealand.
Yeast. 2000 Dec;16(16):1509-18. doi: 10.1002/1097-0061(200012)16:16<1509::AID-YEA638>3.0.CO;2-R.
This report describes the identification and characterization of a retrotransposon, termed Tca5, from the pathogenic yeast Candida albicans. Tca5 has identical 685 bp LTRs flanking 4218 bp of internal sequence within which lies a single long ORF. Immediately internal to the left LTR is a primer binding site complementary to an internal portion of the initiator methionine tRNA and upstream of the right LTR is a polypurine tract. The ORF predicts a protein containing all the conserved motifs characteristic of Gag, protease, integrase, reverse transcriptase and RNaseH. Genomic Southern blots probed with Tca5 sequences show that it is a low copy number element and is present at different loci in different strains. This, together with the apparently intact structure of Tca5, suggests that it has transposed very recently. Potentially full-length Tca5 transcripts were detected in some strains raising the possibility that some copies of Tca5 may still be active. Phylogenetic analyses and other sequence comparisons suggest that Tca5 is most closely related to the Ty5 element of Saccharomyces cerevisiae and S. paradoxus. The nucleotide sequence of Tca5 has been submitted to GenBank under Accession No. AF093417.
本报告描述了从致病性酵母白色念珠菌中鉴定和表征一种逆转录转座子，命名为Tca5。Tca5两侧是相同的685 bp长末端重复序列（LTR），中间是4218 bp的内部序列，其中有一个单一的长开放阅读框（ORF）。在左侧LTR内部紧邻的是一个与起始甲硫氨酸tRNA内部部分互补的引物结合位点，在右侧LTR上游是一个多聚嘌呤序列。该ORF预测的蛋白质包含Gag、蛋白酶、整合酶、逆转录酶和核糖核酸酶H的所有保守基序。用Tca5序列进行的基因组Southern杂交表明，它是一个低拷贝数元件，存在于不同菌株的不同位点。这与Tca5明显完整的结构一起表明，它最近才发生转座。在一些菌株中检测到潜在的全长Tca5转录本，这增加了一些Tca5拷贝可能仍然活跃的可能性。系统发育分析和其他序列比较表明，Tca5与酿酒酵母和奇异酵母的Ty5元件关系最为密切。Tca5的核苷酸序列已提交至GenBank，登录号为AF093417。
