Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 12 (7), 2901-12

One Member of a gro-ESL-like Chaperonin Multigene Family in Bradyrhizobium Japonicum Is Co-Regulated With Symbiotic Nitrogen Fixation Genes

Affiliations

One Member of a gro-ESL-like Chaperonin Multigene Family in Bradyrhizobium Japonicum Is Co-Regulated With Symbiotic Nitrogen Fixation Genes

H M Fischer et al. EMBO J.

Abstract

This report is concerned with the structural characterization and genetic regulation of new bacterial groES and groEL chaperonin genes, and presents two novelties. The first is the discovery that the nitrogen fixing soybean root nodule bacterium, Bradyrhizobium japonicum, unlike all other prokaryotes investigated so far, possesses a multigene family consisting of five very similar, though not identical, groESL-like genes. The second novelty relates to the finding that these five homologues are expressed to different degrees and, in particular, that one family member (namely groESL3) is induced by a mechanism that does not involve the well-known heat shock response. By contrast, the groESL3 genes are co-regulated together with symbiotic nitrogen fixation genes, in that they are activated by the nitrogen fixation regulatory protein NifA at low oxygen conditions and transcribed from a -24/-12 promoter by the sigma 54 RNA polymerase. Two other members of the groESL gene family are apparently expressed constitutively at different levels, and yet another one is strongly induced by high temperature. As an attractive hypothesis it follows that B. japonicum may modulate its cellular contents of GroES- and GroEL-like chaperonins in response to specific environmental conditions and physiological needs.

Similar articles

See all similar articles

Cited by 58 articles

See all "Cited by" articles

References

    1. J Bacteriol. 1989 Aug;171(8):4162-9 - PubMed
    1. Biochem Biophys Res Commun. 1989 Sep 15;163(2):780-7 - PubMed
    1. J Exp Med. 1989 Oct 1;170(4):1271-83 - PubMed
    1. J Mol Biol. 1989 Nov 5;210(1):65-77 - PubMed
    1. Gene. 1989 Dec 14;84(2):295-302 - PubMed

Publication types

MeSH terms

Feedback