Heteroduplex electron microscopy of phage Mu mutants containing IS1 insertions and chloramphenicol resistance transposons

Chow, L. T., Bukhari, A. I. (July 1978) Heteroduplex electron microscopy of phage Mu mutants containing IS1 insertions and chloramphenicol resistance transposons. Gene, 3 (4). pp. 333-46. ISSN 0378-1119 (Print)0378-1119 (Linking)

URL: http://www.ncbi.nlm.nih.gov/pubmed/365687
DOI: 10.1016/0378-1119(78)90042-2

Abstract

We have examined by electron microscopy the DNA heteroduplexes of six bacteriophage Mu mutants, Mu X cam, generated by the insertion of the Tn9 transposon for chloramphenicol resistance. Tn9 was found to be 2.8 +/- 0.2 kilobases (kb) in length and to consist of a cam determinant flanked by two IS1 sequences arranged in a direct order. In two of the six Mu X cam mutants, the Tn9 insertion was at a fixed location, 3.9 kb from the left, or c, end. In the other four mutants, the position of the insertion varied, even though the lysogenic cultures induced were grown from single colonies. The insertion was located at either 3.3 kb, 3.9 kb, or, less frequently, at 4.4 kb from the left end of the DNA. Furthermore, at low frequencies, the insertions were found to be in an orientation opposite to what predominated in the preparation. Thus, Tn9 in the Mu X cam mutants examined could appear to undergo rapid rearrangements during Mu growth or over a few generations of cell growth. One of the Tn9 insertion sites was apparently the same as that for a 0.8 kb insertion found in a Mu X mutant. This latter insertion was identified as an IS1 sequence. The DNA molecules from all the Mu X cam mutant phage particles were found to be missing the bacterial DNA at the S (right) end, along with a variable amount of the adjoining Mu DNA in the beta region. This observation supports the headful packaging model for Mu DNA.

Item Type: Paper
Uncontrolled Keywords: *Chloramphenicol Coliphages/*genetics DNA, Bacterial *DNA, Recombinant DNA, Viral Escherichia coli/genetics Microscopy, Electron Mutation *R Factors
Subjects: organs, tissues, organelles, cell types and functions > cell types and functions > cell types > bacteriophage
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > bacteriophage
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > bacteriophage

bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > transposons
CSHL Authors:
Communities: CSHL labs
Depositing User: Matt Covey
Date: July 1978
Date Deposited: 25 Aug 2016 13:35
Last Modified: 25 Aug 2016 13:35
Related URLs:
URI: http://repository.cshl.edu/id/eprint/33324

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