Some features of the mutability of bacteria during nonlethal selection.
We describe the mutability of the Trp(-) chromosomal +1 frameshift mutation trpE7999 during nonlethal selection, finding that the appearance of Trp(+) revertants behaves similarly to that of episomal Lac(+) revertants. In addition, we show that a feature of the Lac(+) and Trp(+) mutability is the accumulation of Trp(+) and Lac(+) revertants with additional unselected mutations, most of which are not due to heritable mutators. The cells undergoing nonlethal selection apparently experience an epigenetic change resulting in a subset of bacteria with elevated mutability that often remain hypermutable for the duration of selection. The epigenetic change provoked by nonlethal selection appears to be mediated by a unique function provided by the F'128 episome.
Godoy
V G
VG
Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Gizatullin
F S
FS
Fox
M S
MS
D001419:Bacteria / Q000235:genetics*; D001426:Bacterial Proteins; D002876:Chromosomes, Bacterial; D007763:Lac Operon / Q000235:genetics; D009154:Mutation; D012097:Repressor Proteins / Q000235:genetics; D012641:Selection, Genetic; D029968:Escherichia coli Proteins
D001426:Bacterial Proteins; D012097:Repressor Proteins; C027190:TRPR protein, E coli; D029968:Escherichia coli Proteins