Overlapping activator sequences determined for two oppositely oriented promoters in halophilic Archaea.
Transcription of the genomic region involved in gas vesicle formation in Halobacterium salinarum (p-vac) and Haloferax mediterranei (mc-vac) is driven by two divergent promoters, P(A) and P(D), separated by only 35 nt. Both promoters are activated by the transcription activator GvpE which in the case of P(mcA) requires a 20-nt sequence (UAS) consisting of two conserved 8-nt sequence portions located upstream of BRE. Here, we determined the two UAS elements in the promoter region of p-vac by scanning mutageneses using constructs containing P(pD) (without P(pA)) fused to the bgaH reporter gene encoding an enzyme with beta-galactosidase activity, or the dual reporter construct pApD with P(pD) fused to bgaH and P(pA) to an altered version of gvpA. The two UAS elements found exhibited a similar extension and distance to BRE as previously determined for the UAS in P(mcA). Their distal 8-nt portions almost completely overlapped in the centre of P(pD)-P(pA), and mutations in this region negatively affected the GvpE-mediated activation of both promoters. Any alteration of the distance between BRE and UAS resulted in the loss of the GvpE activation, as did a complete substitution of the proximal 8-nt portion, underlining that a close location of UAS and BRE was very important.
Institut für Mikrobiologie und Genetik, TU Darmstadt, Schnittspahnstrasse 10, D-64287 Darmstadt, Germany.
Martina
M
Bauer
Larissa
L
Marschaus
Muriel
M
Reuff
Verena
V
Besche
Simone
S
Sartorius-Neef
Felicitas
F
Pfeifer
D019843:Archaeal Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D017124:Conserved Sequence; D019848:Gene Expression Regulation, Archaeal; D019617:Halobacterium salinarum / Q000235:genetics*; D019623:Haloferax mediterranei / Q000235:genetics; D019622:Haloferax volcanii / Q000235:genetics; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism; D015533:Transcriptional Activation
D019843:Archaeal Proteins; D011506:Proteins; D015534:Trans-Activators; C038524:gas vesicle protein