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The Operon as a Conundrum of Gene Dynamics and Biochemical Constraints: What We Have Learned from Histidine Biosynthesis.

Published version

Published version
Peer-reviewed

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Authors

Esposito, Antonia 
Liò, Pietro 

Abstract

Operons represent one of the leading strategies of gene organization in prokaryotes, having a crucial influence on the regulation of gene expression and on bacterial chromosome organization. However, there is no consensus yet on why, how, and when operons are formed and conserved, and many different theories have been proposed. Histidine biosynthesis is a highly studied metabolic pathway, and many of the models suggested to explain operons origin and evolution can be applied to the histidine pathway, making this route an attractive model for the study of operon evolution. Indeed, the organization of his genes in operons can be due to a progressive clustering of biosynthetic genes during evolution, coupled with a horizontal transfer of these gene clusters. The necessity of physical interactions among the His enzymes could also have had a role in favoring gene closeness, of particular importance in extreme environmental conditions. In addition, the presence in this pathway of paralogous genes, heterodimeric enzymes and complex regulatory networks also support other operon evolution hypotheses. It is possible that histidine biosynthesis, and in general all bacterial operons, may result from a mixture of several models, being shaped by different forces and mechanisms during evolution.

Description

Peer reviewed: True

Keywords

histidine metabolic pathway, metabolon, operon evolution, piecewise model, thermophily, Histidine, Evolution, Molecular, Operon, Bacteria, Multigene Family

Journal Title

Genes (Basel)

Conference Name

Journal ISSN

2073-4425
2073-4425

Volume Title

Publisher

MDPI AG
Sponsorship
Adriano Buzzati-Traverso Foundation (Pavia, Italy) (841)