Open AccessMolecular Characterization of hsp20 , Encoding a Small Heat Shock Protein of Bifidobacterium breve UCC2003
Author(s) -
Marco Ventura,
Carlos Canchaya,
Ziding Zhang,
Gerald F. Fitzgerald,
Douwe van Sinderen
Publication year - 2007
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.02496-06
Subject(s) - biology , gene , heat shock protein , genome , genetics , phylogenetic tree
Small heat shock proteins (sHSPs) are members of a diverse family of stress proteins that are important in cells to protect proteins under stressful conditions. Genome analysis ofBifidobacterium breve UCC2003 revealed a single sHSP-encoding gene, which was classified as ahsp20 gene by comparative analyses. Genomic surveillance of available genome sequences indicated thathsp20 homologs are not widely distributed in bacteria. In members of the genusBifidobacterium , this gene appears to be present in only 7 of the 30 currently described species. Moreover, phylogenetic analysis using all available bacterial and eukaryotic sHSP sequences revealed a close relationship between bifidobacterial HSP20 and the class B sHSPs found in members of the divisionFirmicutes . The results of this comparative analysis and variation in codon usage content suggest thathsp20 was acquired by certain bifidobacteria through horizontal gene transfer. Analysis by slot blot, Northern blot, and primer extension experiments showed that transcription ofhsp20 is strongly induced in response to severe heat shock regimens and by osmotic shock.