The role of replication-induced chromosomal copy numbers in spatio-temporal gene regulation and evolutionary chromosome plasticity
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Philipps-Universität Marburg
Abstract
For a coherent response to environmental changes, bacterial evolution has
formed a complex transcriptional regulatory system comprising classical DNA
binding proteins sigma factors and modulation of DNA topology. In this study,
we investigate replication-induced gene copy numbers - a regulatory concept
that is unlike the others not based on modulation of promoter activity but on
replication dynamics. We show that a large fraction of genes are predominantly
a?ected by transient copy numbers and identify cellular functions and central
pathways governed by this mechanism in Escherichia coli. Furthermore, we show
quantitatively that the previously observed spatio-temporal expression pattern
between di?erent growth phases mainly emerges from transient chromosomal
copy numbers.We extend the analysis to the plant pathogen Dickeya dadantii and
the biotechnologically relevant organism Vibrio natriegens. The analysis reveals a
connection between growth phase dependent gene expression and evolutionary
gene migration in these species. A further extension to the bacterial kingdom
indicates that chromosome evolution is governed by growth rate related transient
copy numbers.