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1.
Several unit-length minicircles from the kinetoplast DNA of Leishmania tarentolae were cloned into pBR322 and into M13 phage vectors. The complete nucleotide sequences of three different partially homologous minicircles were obtained. The molecules contained a region of approx. 80% sequence homology extending for 160–270 bp and a region unique to each minicircle. A 14-mer was found to be conserved in all kinetoplast minicircle sequences reported to date. The frequency distributions of various minicircle sequence classes in L. tarentolae were obtained by quantitative gel electrophoresis and by examination of the “T ladder” patterns of minicircles randomly cloned into M13 at several sites. By these methods we could assign approx. 50% of the total minicircle DNA into a minimum of five sequence classes. A sequence-dependent polyacrylamide gel migration abnormality was observed with several minicircle fragments both cloned and uncloned. The abnormality was dependent on the presence of a portion of the conserved region of the minicircle. 相似文献
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Shira Weingarten-Gabbay Susan Klaeger Siranush Sarkizova Leah R. Pearlman Da-Yuan Chen Kathleen M.E. Gallagher Matthew R. Bauer Hannah B. Taylor W. Augustine Dunn Christina Tarr John Sidney Suzanna Rachimi Hasahn L. Conway Katelin Katsis Yuntong Wang Del Leistritz-Edwards Melissa R. Durkin Christopher H. Tomkins-Tinch Pardis C. Sabeti 《Cell》2021,184(15):3962-3980.e17
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The pyr4 gene of Neurospora crassa, which codes for orotidine-5'-phosphate decarboxylase, is capable of transforming an Aspergillus nidulans pyrG mutant by chromosomal integration, despite low homology between the transforming DNA and the recipient genome. Integration of pFB6, a plasmid carrying pyr4 and capable of replication in Escherichia coli, was not observed at the pyrG locus. The efficiency of transformation was considerably enhanced (50-100 fold) by inclusion in the transforming vector of a 3.5-kb A.nidulans chromosomal sequence, ans1. Although this sequence was isolated on the basis of replicating activity in Saccharomyces cerevisiae, there was no evidence for such activity in A.nidulans. Part of the ans1 fragment appears to be reiterated in the A.nidulans genome, though it is not yet clear whether this is directly responsible for the high transformation frequency. The efficiency of transformation of A.nidulans by plasmids bearing ans1, using an improved protocol, was approx. 5 X 10(3) stable transformants per microgram of plasmid DNA. 相似文献
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The araBAD operon of Salmonella typhimurium LT2. I. Nucleotide sequence of araB and primary structure of its product, ribulokinase 总被引:6,自引:0,他引:6
Hybrid plasmids containing the araBAD operon of Salmonella typhimurium LT2 were characterized by Southern blot and genetic analyses. The nucleotide sequence of araB was determined. The araB gene product, ribulokinase (EC 2.7.1.16), was purified and the results of amino acid composition analysis and partial amino acid sequence are in agreement with predictions from the DNA sequence. Ribulokinase is 569 amino acid residues long and has a calculated Mr of 61 793. Ribulokinase shares significant homology with xylulose kinase from Escherichia coli. Codon usage in the araB gene does not favor those codons which have intermediate codon-anticodon binding energy. 相似文献
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Nonrandom insertion of Tn5 into cloned human adenovirus DNA 总被引:4,自引:0,他引:4
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