ISSN:
1617-4623
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The molecular basis for lack of phenotypic expression of one chromosome in Bacillus subtilis non-complementing diploid clones (Ncd cells) was investigated. Correlations between chromosomal inactivation and absence of functional transcripts were determined with wild-type prophage ϕ105 or a thermoinducible mutant ϕ105 cts23, on either the expressed or the silent chromosome. It appears that no significant amount of phage mRNA is detectable in Ncd cells carrying the prophage in the inactive chromosome. However, ϕ105 mRNA represents 0.23% of total cellular mRNA in an Ncd strain with the prophage in the expressed chromosome and 0.28% in the parental lysogenic strain. The lack of an mRNA repressor of ϕ105 prophage from the silent chromosome was confirmed by the absence of repressor activity in Ncd clones with a temperature sensitive mutant ϕ105 located in the silent chromosome. After heat induction, no phage production was observed. As expected these clones do not exhibit ϕ105 immunity when superinfected with the same phage. The combined data of the present and previous work suggest that control of phenotypic suppression of Ncd strains should, at the transcription level, involve a different DNA tertiary organisation in one of the two chromosomes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00330893
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