Molecular switches--the ON and OFF of bacterial phase variation.
The expression of most bacterial genes is controlled at the level of transcription via promoter control mechanisms that permit a graded response. However, an increasing number of bacterial genes are found to exhibit an 'all-or-none' control mechanism that adapts the bacterium to more than one environment. One such mechanism is phase variation, traditionally defined as the high-frequency ON<-->OFF switching of phenotype expression. Phase variation events are usually random, but may be modulated by environmental conditions. The mechanisms of phase variation events and their significance within the microbial community are discussed here.
Henderson
I R
IR
Center for Vaccine Development, Department of Pediatrics, University of Maryland School of Medicine, 685 West Baltimore Street, Baltimore, MD 21201, USA. ihenders@umaryland.edu
Owen
P
P
Nataro
J P
JP
D000222:Adaptation, Physiological / Q000235:genetics*; D000595:Amino Acid Sequence; D001419:Bacteria / Q000235:genetics*; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D011995:Recombination, Genetic; D014158:Transcription, Genetic