Selective chromosome amplification in Vibrio cholerae

摘要: Most bacteria have one chromosome but some more than one, as is common in eukaryotes. How multiple chromosomes are maintained remains largely obscure. Here we examined the behaviour of two Vibrio cholerae a function growth rate. At slow rates, both were at copy numbers to per cell. Increasing rate by nutritional shift-up amplified origin-proximal DNA larger (chrI) four copies cell, not that smaller chrII. The latter was when its specific initiator supplied excess or negative regulator deleted. rate-insensitive chrII, whose origin similar origins members major class plasmids, shared all several representative plasmids tested V. cholerae. Also, unlike plasmid replication, chrII replication known be initiated stage cell cycle. Raising number decreased rate, suggesting this might serve repository for necessary potentially deleterious genes.