Phosphate-dependent regulation of the low- and high-affinity transport systems in the model actinomycete Streptomyces coelicolor

Abstract

The transport of inorganic phosphate (P i ) is essential for the growth of all organisms. The metabolism of soil-dwelling Streptomyces species, and their ability to produce antibiotics and other secondary metabolites, are strongly influenced by the availability of phosphate. The transcriptional regulation of the SCO4138 and SCO1845 genes of Streptomyces coelicolor was studied. These genes encode the two putative low-affinity P i transporters PitH1 and PitH2, respectively. Expression of these genes and that of the high-affinity transport system pstSCAB follows a sequential pattern in response to phosphate deprivation, as shown by coupling their promoters to a luciferase reporter gene. Expression of pitH2, but not that of pap-pitH1 (a bicistronic transcript), is dependent upon the response regulator PhoP. PhoP binds to specific sequences consisting of direct repeats of 11 nt in the promoter of pitH2, but does not bind to the pap-pitH1 promoter, which lacks these direct repeats for PhoP recognition. The transcription start point of the pitH2 promoter was identified by primer extension analyses, and the structure of the regulatory sequences in the PhoP-protected DNA region was established. It consists of four central direct repeats flanked by two other less conserved repeats. A model for PhoP regulation of this promoter is proposed based on the four promoter DNA-PhoP complexes detected by electrophoretic mobility shift assays and footprinting studies.

The master regulator PhoP coordinates phosphate and nitrogen metabolism, respiration, cell differentiation and antibiotic biosynthesis: comparison in Streptomyces coelicolor and Streptomyces avermitilis

“…19 Phosphate scavenging, transport, storage and mobilization Rodríguez-García et al, 4 in phosphate shift-down experiments using transcriptomic and proteomic analysis, discovered that the primary response to phoP deletion in S. coelicolor was the increase in expression of many genes that are involved in phosphate scavenging, transport, storage and mobilization. The primary targets of PhoP regulation were genes encoding phosphatases, including phoA, phoC, the phospholipase phoD 15 and the phytase-encoding gene, phyA. 22 The S. coelicolor and S. lividans phyA expression is regulated by phosphate, its transcription is PhoP-dependent and there is a PHO box in the promoter region of the phyA gene.…”

“…14 The Streptomyces PHO boxes are formed by direct repeat units (DRus) of 11 nucleotides, seven nucleotides being well conserved; other characteristics of the PHO boxes have been described previously. 15,16 In S. coelicolor, the most conserved sequence is GTTCACC, obtained from the alignment of the PhoP-binding sites of the best studied PhoP-regulated genes. 5,16,17 The sequence logo representing the PhoP-binding DRus is shown in Figure 1.…”

Is PhoR–PhoP partner fidelity strict? PhoR is required for the activation of the pho regulon in Streptomyces coelicolor

“…Genes under direct control of PhoP constitute the denominated pho regulon. Several PhoP operators have been characterized by protein-DNA binding assays (EMSA and DNase I footprinting) in 60 numerous promoters (Apel et al 2007;Rodriguez-García et al 2007;Sola-Landa et al 2005;Santos-Beneit et al 2008;2009 a,b;. PhoP can act either as a positive regulator, by binding at the -35 region (or nearby), or as a repressor, when bound to the -10 region (i.e.…”

Extracellular sugar phosphates are assimilated by Streptomyces in a PhoP-dependent manner

“…Alternatively the sugar phosphates can be dephosphorylated by extracellular phosphatases, the carbon moiety being taken-up by the usual transport system of the cognate sugar and the P i moiety by known low or high affinity phosphate uptake systems (PitH1 and PitH2, or PstSCAB, (Esteban et al 2008;Santos-Beneit et al 2008). Since all the un-phosphorylated carbon sources tested had no impact on development whereas exogenous supply of P i led to a developmental delay similar (although not identical) to that observed with exSPs (Fig.…”

“…P i , inorganic phosphate, PhoR phosphate limitation two-component histidine kinase, PhoP phosphate limitation response regulator associated to PhoR, PitH1 low-affinity P i transporter under inorganic phosphate excess, PitH2 P i low-affinity transporter under phosphate limitation conditions, PstABC P i high-affinity ABC-transporter. The model is deduced from the compilation of previous works (Sola-Landa et al 2003Diaz et al 2005;Ghorbel et al 2006;Apel et al 2007;Esteban et al 2008;Santos-Beneit et al 2008) Fig. 5 Concentration dependence of the sugar-phosphates effect on Streptomyces development.…”