The Loss of a Large DNA Fragment is Associated with an Aerial Mycelium Negative (Amy-) Phenotype of Streptomyces cattleya

Abstract

Hybridization of various Streptomyces cattleya aerial mycelium negative (Amy-) mutants with a probe containing the gene for argininosuccinate synthetase (pTG17) has revealed the presence of two different types of mutants (stable and unstable). Stable mutants appear to have lost all or part of the region covered by the probe, while the unstable mutants demonstrate no detectable changes in this region. In one group of stable mutants (those demonstrating a partial loss of sequences hybridizing to the probe), a 4.17 kb extrachromosomal element was detected, which hybridized with the pTG17 probe. The significance of this finding is discussed with reference to the genetic instability of the genus Streptomyces.

Genetic instability and DNA amplification in Streptomyces lividans 66

“…In strain 1713 a deletion extends into the internal sequence of the 6.8-kb AUD, and the resident 18. (11,16,21,28,35). We identified, in addition to a previously described example of genetic instability, a second, independent pathway of instability in S. lividans 66.…”

“…The enhancement of this high spontaneous mutability by plasmid-curing agents initially led researchers to propose that these unstable traits might be plasmid encoded (1,10,24). Subsequently several such unstable genes were shown to be located on the chromosomes of wild-type strains, while analysis of variant strains indicated that mutant phenotypes were often due to deletions of chromosomal regions containing these genes (11,16,21,28,35).…”

Cloning and expression in Escherichia coli of a recA homologue from Mycobacterium tuberculosis

“…The interrelationship between the rec and uvr systems in Streptomyces may be essential to an understanding of genetic instability in these organisms (Usdin et al, 1985). The homologous recombination system in Streptomyces appears to be distinct from the DNA repair system, since no UV-sensitive mutants of Streptomyces have been isolated which are recombination-negative (Harold & Hopwood, 1970b, 1972 Media, culture conditions and DNA isolation.…”

DNA Amplification and Genetic Instability inStreptomyces

“…These mutants usually lack the enzyme argininosllccinate synthase (EC 6.3.4.5) and thus can grow on argininosllccinate but not on citrulline (Sermonti et aI., 1978;Redshaw et al, 1979;Matsubara-Nakano, Kataoka and Ogawara, 1980). Recently it has been shown that the Arg-mutations in several species arise from deletion of the gene for argininosuccinate synthase, arg G (Ishihara, Nakano and Ogawara, 1985;Usdin et al, 1985).…”

“…In S. kasugaenisis, Arg-mutants had lost a plasmid that reappeared in Arg+ revertants (Nakano, Ozawa and Ogawara, 1980). In S. cattleya, one Arg-mutant had transferred part of the arg G gene to a plasmid (Usdin et a/., 1985). References: (1) Rcdshuw et ell.…”