The Escherichia coli gapA gene is transcribed by the vegetative RNA polymerase holoenzyme E sigma 70 and by the heat shock RNA polymerase E sigma 32

Abstract

Escherichia coli D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is produced by the gapA gene and is structurally related to eukaryotic GAPDHs. These facts led to the proposal that the gapA gene originated by a horizontal transfer of genetic information. The yields and start sites of gapA mRNAs produced in various fermentation conditions and genetic contexts were analyzed by primer extension. The transcriptional regulatory region of the gapA gene was found to contain four promoter sequences, three recognized by the vegetative RNA polymerase Eff70 and one recognized by the heat shock RNA polymerase E&32. Transcription ofgapA by Eu32 is activated in the logarithmic phase under conditions of starvation and of heat shock Using a GAPDH-strain, we found that GAPDH production has a positive effect on cell growth at 43°C. Thus, E. coli GAPDH displays some features of heat shock proteins. One of the gapA promoter sequences transcribed by Eu70 is subject to catabolic repression. Another one has growth phase-dependent efficiency. This complex area of differentially regulated promoters allows the production of large amounts of gapA transcripts in a wide variety of environmental conditions. On the basis of these data, the present view of Eu32 RNA polymerase function has to be enlarged, and the various hypotheses on E. coli gapA gene origin have to be reexamined.The NAD+-dependent phosphorylating D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which converts D-glyceraldehyde-3-phosphate into 1,3-diphosphoglycerate (22), is a key enzyme of the glycolytic and gluconeogenesis pathways. In eubacteria (5,14,17,46) and archaebacteria (4), the GAPDH gene (gap) belongs to a cluster of genes coding for several glycolytic enzymes: 3-phosphoglycerate kinase (pgk), class II fructose 1,6-bisphosphate aldolase (fda), and triosephosphate isomerase (tpi). A peculiar situation is observed in Escherichia coli, in which the gapB gene, located in this cluster, does not produce GAPDH activity (2, 25). The active gapA gene and the pgk gene are 22.6 min apart on the E. coli chromosome (7,50). In addition, the gapA gene codes for a protein which has stronger homology with mammalian GAPDHs than with bacterial enzymes (6). A eukaryotic origin has thus been proposed for the gapA gene: enterobacteria would have acquired the gapA gene through a horizontal transmission of genetic information, concomittant with the loss of activity of the gapB gene (2,16,36 recognized by the RNA polymerase holoenzyme EC70, which is formed by association of the holoenzyme with the major sigma factor, u70 (24). A few subsets of genes that respond to various environmental or nutritional changes require specific recognition by RNA polymerase associated with the alternative sigma factor u32 (21), crE (18,52), 0k54 (26), or as (39). The heat shock response mediated by the Eu32 RNA polymerase holoenzyme has been the subject of several studies (for reviews, see references 8 and 40). When E. coli cells growing at 30°C are shifted to 42°C, the rate of synthesis of the so-call...

Transcription of the mutL repair, miaA tRNA modification, hfq pleiotropic regulator, and hflA region protease genes of Escherichia coli K-12 from clustered Esigma32-specific promoters during heat shock

“…9) at low and high temperatures. Many members of the E 32 transcription regulon are dually transcribed from E 70 promoters (8,39,65,76), as is the case for the genes in the amiB-mutL-miaA-hfq-hflX-hflK-hflC superoperon (Fig. 1).…”

Regulation of the ndh gene of Escherichia coli by integration host factor and a novel regulator, Arr

“…E. coli RJ1801 (fis-985 strlspc; Ball et al, 1992) was the source of the proteins used in this study. The effects of IHF on ndh expression were monitored using JRG1990 (Afac hzdh-ZacZ) and JRG1991 (Alac fnr-250 Indh-lacZ), which are AG211 monolysogens of RK4353 and RK5279 (Spiro et al, 1989), respectively, and two derivatives, JRG3232 (Alac ihfA Andh-lac2) and JRG3234 ( A h fnr ihfA hzdh-lacZ), constructed by Plvir-mediated transduction with a donor strain containing the ihfAA82tetR mutation (Schroder (Charpentier & Branlant, 1994); and JRG3628, a glyceraldehyde-3-phosphate dehydrogenase-overproducing strain (DH5a containing the gap expression plasmid pBS : : EcogapA) (Charpentier & Branlant, 1994). The effects on ndh expression of independent substitution of two bases within Arr I were monitored using three derivatives of the low-copy-number, broad-host-range vector pRW5O (kindly provided by Professor s. J. w. Busby, University of Birmingham) in both fnr+ (RK4353) and fnr (RK5279) backgrounds.…”

Expression of the gap gene encoding glyceraldehyde-3-phosphate dehydrogenase of Streptomyces aureofaciens requires GapR, a member of the AraC/XylS family of transcriptional activators The GenBank/EMBL/DDBJ accession number for the sequence described in this paper is U21191.

“…Since a mutation in the gapA gene abolished the GAPDH activity, the gapA gene was considered to be the only active GAPDH-encoding gene in E. coli (Branlant et al, 1983 ;Della Seta et al, 1997). Analysis of gapA transcription revealed a complex regulation comprising four tandemly organized promoters (Charpentier & Branlant, 1994). The gapB-pgk operon is directed by a single promoter (Charpentier et al, 1998).…”