Hartree, David E. (1989) Cloning and characterisation of developmental genes in "Myxococcus xanthus" using a plasmid based promoter probe. PhD thesis, University of Warwick.

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Abstract

An integrative promoter-probe plasmid was used as a cloning vector for randomly cut DNA from Myxococcus xanthus. The resulting chromosomal library of gene fusions to the IacZ gene was returned to M. xanthus using P1mediated transduction. Transductants were screened for ß-galactosidase expression under both vegetative and sporulation conditions. Several strains were found which showed increases in expression during sporulation. This indicated that the IacZ gene had become fused to a sporulation gene.

More detailed studies were carried out upon two of the gene fusions. Fusion 1sgA1 -> 1 acZ was transduced into other genetic backgrounds including backgrounds with known mutations which block sporulation. The gene fusion showed increased expression under starvation conditions even in mutants unable to sporulate. The 1sgA1 gene, therefore, appears to be activated early during development. A second gene fusion 1sgB2> IacZ was found to be expressed strongly in circumstances were spores were forced to form outside of fruiting bodies. It should . therefore, appear to be a conditional sporulation gene. There is virtually no increase in activity when sporulation occurs in a wild type background.

Experiments were carried out using transposon mutagenesis of the 1sgA1 and 1sgB2 genes. No mutant strains could be obtained with insertions in the region of the 1sgA1 gene. This suggests that the region is essential to the growth of the cell. Insertions were readily obtained in the 1sgB2 region. However, no mutant phenotype was observed. Transposon mutagenesis upon the 1sgB2˃;IacZ fusion was employed to locate the 1sgB2 promoter. The location of the promoter was defined to within a region of 700 base pairs

Item Type:	Thesis or Dissertation (PhD)
Subjects:	Q Science > QR Microbiology
Library of Congress Subject Headings (LCSH):	Myxococcales -- Genetics, Myxococcus xanthus, Molecular biology, Cytology, Biochemistry
Official Date:	July 1989
Dates:	Date Event July 1989 Submitted
Institution:	University of Warwick
Theses Department:	Department of Biological Sciences
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Hodgson, D. A.(David A.)
Sponsors:	Sussex European Research Centre
Extent:	xviii, 274 leaves : illustrations
Language:	eng

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