amfC plays a regulatory role in aerial mycelium formation in Streptomyces griseus and is distributed widely among Streptomyces species. Disruption of the chromosomal amfC gene in Streptomyces coelicolor A3(2) severely reduced formation of aerial hyphae, indicating that amfC is important in morphological development. In addition, the disruption caused S. coelicolor A3(2) M130 to produce much less actinorhodin, and to produce undecylprodigiosin at a later stage of growth, indicating that amfC also regulates secondary metabolism. S1 nuclease mapping showed that transcription of actII-ORF4, the pathway-specific transcriptional activator in the act gene cluster, was greatly reduced in the amfC disruptants. The defect in secondary metabolite formation was suppressed or overcome by a mutation in sre-1. Consequently, an amfC-disrupted strain derived from S. coelicolor A3(2) M145, an actinorhodin-overproducing strain due to the sre-1 mutation, still produced a large amount of actinorhodin. Extra copies of amfC in strains M130 and M145 did not change spore-chain morphology or secondary metabolite formation. However, the spores in these strains remained white even after prolonged incubation. Since only spore pigmentation was affected, all known whi genes, except whiE, responsible for the polyketide spore pigment formation, were assumed to function normally. S1 nuclease mapping showed that transcription of whiEP1, one of the promoters in the whiE locus, was reduced in S. coelicolor A3(2) containing extra copies of amfC. Introducing amfC into several other Streptomyces species, such as Streptomyces lividans, Streptomyces lavendulae and Streptomyces lipmanii, also abolished spore pigment formation. An increase in the amount of AmfC appeared to disturb the maturation of spores.
BeckE., LudwigG., AuerswaldA., ReissB., SchallerH.1982; Nucleotide sequence and exact localisation of the neomycin phosphotransferase gene from transposon Tn5.. Gene 19:327–336[CrossRef]
BystrykhL. V., Fernándes-MorenoM. A., HerremaJ. K., MalpartidaF., HopwoodD. A., DijkhuizenL. 1996; Production of actinorhodin-related ‘‘blue’’ pigments by Streptomyces coelicolor A3(2). J Bacteriol 178:2238–2244
ChaterK. F.1984; Morphological and physiological differentiation in Streptomyces. In Microbial Development pp 89–115Edited byLosickR., ShapiroL. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory;
ChaterK. F.1989; Sporulation in Streptomyces. In Regulation of Procaryotic Development: Structural and Functional Analysis of Bacterial Sporulation and Germination pp 277–299Edited bySmithI., SlepeckyR. A., SetlowP. Washington, DC: American Society for Microbiology;
DavisN. K., ChaterK. F.1990; Spore colour in Streptomyces coelicolor A3(2) involves the developmentally regulated synthesis of a compound biosynthetically related to polyketide antibiotics. Mol Microbiol 4:1679–1691[CrossRef]
Fernándes-MorenoM. A., CaballeroJ. L., HopwoodD. A., MalpartidaF. 1991; The act cluster contains regulatory and antibiotic export genes, direct targets for translational control by the bldA tRNA gene of Streptomyces.. Cell 66:769–780[CrossRef]
FlorianoB., BibbM.1996; afsR is a pleiotropic but conditionally required regulatory gene for antibiotic production in Streptomyces coelicolor A3(2). Mol Microbiol 21:385–396[CrossRef]
FujiiT., GramajoH. C., TakanoE., BibbM. J.1996; redD and actII-ORF4, pathway-specific regulatory genes for antibiotic production in Streptomyces coelicolor A3(2), are transcribed in vitro by an RNA polymerase holoenzyme containing σhrdD. J Bacteriol 178:3402–3405
HaraO., HorinouchiS., UozumiT., BeppuT.1983; Genetic analysis of A-factor synthesis in Streptomyces coelicolor A3(2) and Streptomyces griseus.. J Gen Microbiol 129:2939–2944
HillemannD., PühlerA., WohllebenW.1991; Gene disruption and gene replacement in Streptomyces via single stranded DNA transformation of integration vectors. Nucleic Acids Res 19:727–731[CrossRef]
HopwoodD. A., BibbM. J., ChaterK. F., JanssenG. R., MalpartidaF., SmithC. P.1986; Regulation of gene expression in antibiotic-producing Streptomyces. In Regulation of Gene Expression – 25 Years On pp 251–276Edited byBoothI. R., HigginsC. F. Cambridge: Cambridge University Press;
HorinouchiS., BeppuT.1994; A-factor as a microbial hormone that controls cellular differentiation and secondary metabolism in Streptomyces griseus.. Mol Microbiol 12:859–864[CrossRef]
HorinouchiS., FuruyaK., NishiyamaM., SuzukiH., BeppuT.1987; Nucleotide sequence of the streptothricin acetyltransferase gene from Streptomyces lavendulae and its expression in heterologous hosts. J Bacteriol 169:1929–1937
KakinumaS., TakadaY., IkedaH., TanakaH., OmuraS.1991; Cloning of large DNA fragments, which hybridize with actinorhodin biosynthesis genes, from kalafungin and nanaomycin A methyl ester and identification of genes for kalafungin biosynthesis of the kalafungin producer. J Antibiot 44:995–1005[CrossRef]
KelemenG. H., BrianP., FlärdhK., ChamberlinL., ChaterK. F., ButtnerM. J.1998; Developmental regulation of transcription of whiE, a locus specifying the polyketide spore pigment in Streptomyces coelicolor A3(2). J Bacteriol 180:2515–2521
KudoN., KimuraM., BeppuT., HorinouchiS.1995; Cloning and characterization of a gene involved in aerial mycelium formation in Streptomyces griseus.. J Bacteriol 177:6401–6410
OchiK., HosoyaY.1998; Genetic mapping and characterization of novel mutations which suppress the effect of a relC mutation on antibiotic production in Streptomyces coelicolor A3(2). J Antibiot 51:592–595[CrossRef]
OnakaH., NakagawaT., HorinouchiS.1998; Involvement of two A-factor receptor homologues in Streptomyces coelicolor A3(2) in the regulation of secondary metabolism and morphogenesis. Mol Microbiol 28:743–753
RydingN. J., KelemenG. H., WhatlingC. A., FlärdhK., ButtnerM. J., ChaterK. F.1998; A developmentally regulated gene encoding a repressor-like protein is essential for sporulation in Streptomyces coelicolor A3(2). Mol Microbiol 29:343–357[CrossRef]
ShimaJ., HeskethA., OkamotoS., KawamotoS., OchiK.1996; Induction of actinorhodin production by rpsL (encoding ribosomal protein S12) mutations that confer streptomycin resistance in Streptomyces lividans and Streptomyces coelicolor A3(2). J Bacteriol 178:7276–7284
Sollner-WebbB., ReederR. H.1979; The nucleotide sequence of the initiation and termination sites for ribosomal RNA transcription in X. laevis.. Cell 18:485–499[CrossRef]
TakamatsuS., KunohH., IshizakiH.1976; Scanning electron microscopy observations on the perithecia of several powdery mildew fungi. I. Erysiphe and Sphaerotheca.. Trans Mycol Soc Jpn 17:409–417
UedaK., MiyakeK., HorinouchiS., BeppuT.1993; A gene cluster involved in aerial mycelium formation in Streptomyces griseus encodes proteins similar to the response regulators of two-component regulatory systems and membrane translocators. J Bacteriol 175:2006–2016
UedaK., HshehC.-W., TosakiT., ShinkawaH., BeppuT., HorinouchiS.1998; Characterization of an A-factor-responsive repressor for amfR essential for onset of aerial mycelium formation in Streptomyces griseus.. J Bacteriol 180:5085–5093
WardJ. M., JanssenG. R., KieserT., BibbM. J., ButtnerM. J., BibbM. J.1986; Construction and characterization of a series of multi-copy promoter-probe plasmid vectors for Streptomyces using the aminoglycoside phosphotransferase gene from Tn5 as indicator. Mol Gen Genet 203:468–478[CrossRef]
Involvement of amfC in physiological and morphological development in Streptomyces coelicolor A3(2)The GenBank accession number for the amfC promoter sequence reported in this paper is D63677.