In silico identification of functional divergence between the multiple groEL gene paralogs in Chlamydiae

Abstract

Background: Heat-shock proteins are specialized molecules performing different and essential roles in the cell including protein degradation, folding and trafficking. GroEL is a 60 Kda heat-shock protein ubiquitous in bacteria and has been regarded as an important molecule implicated in chronic inflammatory processes caused by Chlamydiae infections. GroEL in Chlamydiae became duplicated at the origin of the Chlamydiae lineage presenting three distinct molecular chaperones, namely the original protein GroEL1 (Ct110), and its paralogous proteins GroEL2 (Ct604) and GroEL3 (Ct755). These chaperones present differential and independent expressions during the different stages of Chlamydiae infections and have been suggested to present differential physiological and regulatory roles.

16S rRNA-, GroEL- and MucZ-based assessment of the taxonomic position of 'Rickettsiella melolonthae' and its implications for the organization of the genus Rickettsiella

“…In a preliminary study using C. burnetii gene sequences as a query, we identified two identical rrs genes, as well as single copies of the mucZ and the groEL genes in the genome of Rickettsiella grylli. The finding of only a single copy of the groEL gene was in contrast to the situation usually found in chlamydial genomes where duplication of groEL genes is the rule (McNally & Fares, 2007).…”

“…In a preliminary study using C. burnetii gene sequences as a query, we identified two identical rrs genes, as well as single copies of the mucZ and the groEL genes in the genome of Rickettsiella grylli. The finding of only a single copy of the groEL gene was in contrast to the situation usually found in chlamydial genomes where duplication of groEL genes is the rule (McNally & Fares, 2007).In this study, using the 16S rRNA gene and the GroEL and MucZ proteins as taxonomic markers, we report the first molecular sequence data for a Rickettsiella strain belonging to the type species Rickettsiella popilliae. We investigated whether these data: (i) corroborate the previously merely assumed assignment of Rickettsiella popilliae to the class Gammaproteobacteria, (ii) support the current family level classification of the genus Rickettsiella within the order Legionellales, and (iii) help to elucidate the internal taxonomic structure of the genus Rickettsiella, with particular emphasis on the validity of current species delineations and species-pathotype synonymies.…”

Cpn20: Siamese twins of the chaperonin world

“…Bradyrhizobium japonicum was shown to have five different cpn60 genes, some constitutive, some heat-induced and one regulated together with nitrogen-fixation genes (Fischer et al 1993). Chlamydiae express three divergent paralogs of cpn60 during different stages of Chlamydiae infection (McNally and Fares 2007). In Rhizobium leguinosarum, cpn60 operons were shown to exhibit unique mechanisms for control of expression.…”

Distribution and evolution of short tandem repeats in closely related bacterial genomes

“…Chlamydiales comprise a monophyletic group that is phylogenetically well separated from other bacterial taxa (Stephens et al, 1998;Kalman et al, 1999;Read et al, 2000Read et al, , 2003Shirai et al, 2000;Chen et al, 2007). Their genome evolution has recently been investigated by bioinformatic methods (Ortutay et al, 2003;McNally and Fares, 2007). These features make these genomes ideal for a comparative analysis.…”

“…The increasing number of E. coli strains with known genomes offers a unique opportunity to analyze SSR evolution in these very closely related bacteria (Blattner et al, 1997;Hayashi et al, 2001;Perna et al, 2001;Welch et al, 2002). We analyzed 4 Escherichia genomes used also in other studies (Azad and Lawrence, 2007;McNally and Fares, 2007).…”