ISSN:
1617-4623
Keywords:
Carotenoid biosynthesis
;
Phase transition
;
Phototrophic bacterium
;
Rhodobacter sphaeroides
;
Spontaneous frameshifts
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The synthesis of carotenoids in strain 2.4.1 of the phototrophic bacterium Rhodobacter sphaeroides is spontaneously turned on and off at a high frequency (10−5 per cell per generation) giving rise alternatively to red (wild type) and green (mutant) clones. The crtD gene is not functional in green mutants as a consequence of the spontaneous addition of a guanosine in a stretch of seven guanosines located in the 5′-terminal coding region of this gene originating a frameshift. All spontaneous wild-type revertants isolated from green mutants had recovered the crtD gene function by loss of one of these reiterated guanosines. The transition Crt+ → Crt− → Crt+, is strain-dependent, since Crt+ clones were not detected in ethyl methane sulphonate (EMS)-induced CrtD− mutants of two other strains of R. sphaeroides (WS22 and RS630) which harbour a recombinant plasmid containing the crtD gene from a spontaneous CrtD− mutant of strain 2.4.1 of R. sphaeroides.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00299139
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