期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1983
卷号：80
期号：8
页码：2201-2205
DOI：10.1073/pnas.80.8.2201
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We have recently characterized a transposable element, ISH1, which inactivates the bacterio-opsin (BO) gene in two purple membrane-deficient (Pum-) mutants of Halobacterium halobium. Examination of nine additional Pum- mutants now shows that in all of these the BO gene has been inactivated by insertion of one of two types of transposable elements. Four Pum- strains contain ISH1 within the BO gene, probably at the same site that we have previously characterized. A second element, ISH2, which is present in four more strains, inserts at multiple sites within the BO coding sequence. Significantly, another Pum- strain contains the ISH2 element 102 nucleotides upstream from the initiator codon for BO. ISH2, which is 520 nucleotides long, is the smallest insertion sequence known. Its sequence has been determined: it is A + T-rich (53%), contains a 19-base-pair inverted repeat at its termini, and, interestingly, duplicates either 10 or 20 base pairs at the target site during insertion. ISH2 is present in multiple copy numbers in the genome and contains several relatively short open reading frames.
