ISSN:
1617-4623
Keywords:
Cyclobutane pyrimidine dimers
;
Non-instructive mutagenic lesions
;
Escherichia coli
;
Single specific mutagenic lesion
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The lesions produced by SOS-dependent mutagens in Escherichia coli are commonly referred to as non-pairing or non-instructive. Although these terms are likely to be appropriate for some lesions, particularly the abasic site, for others, such as the cyclobutane dimer, their suitability is open to question. To address this question, we have compared the error frequencies and spectra that result when a uniquely located T-T sequence, carried in a single-stranded vector, contains either a cis-syn or a trans-syn cyclobutane dimer, or when either the 5′T or 3′T is converted to an abasic site. The data suggest that the high accuracy with which the dimer-containing templates are replicated is unlikely to be the consequence of polymerase preference for the non-instructive insertion of dAMP. Similarly, mis-pairing, rather than non-pairing, is likely to cause mutations. Cyclobutane dimers seem therefore to be misinstructive rather than non-instructive lesions, and the common feature shared by SOS-inducing lesions is more their ability to block replication than inability to form correct base pairs.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00283040
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