Cloning and analysis of a gene cluster from Streptomyces coelicolor that causes accelerated aerial mycelium formation in Streptomyces lividans.
We describe the cloning and analysis of two overlapping DNA fragments from Streptomyces coelicolor that cause aerial mycelium to appear more rapidly than usual when introduced into Streptomyces lividans on a low-copy-number plasmid vector. Colonies of S. lividans TK64 harboring either clone produce visible aerial mycelia after only 48 h of growth, rather than the usual 72 to 96 h. From deletion and sequence analysis, this rapid aerial mycelium (Ram) phenotype appears to be due to a cluster of three genes that we have designated ramA, ramB, and ramR. Both ramA and ramB potentially encode 65-kDa proteins with homology to ATP-dependent membrane-translocating proteins. A chromosomal ramB disruption mutant of S. lividans was found to be severely defective in aerial mycelium formation. ramR could encode a 21-kDa protein with significant homology to the UhpA subset of bacterial two-component response regulator proteins. The overall organization and potential proteins encoded by the cloned DNA suggest that this is the S. coelicolor homolog of the amf gene cluster that has been shown to be important for aerial mycelium formation in Streptomyces griseus. However, despite the fact that the two regions probably have identical functions, there is relatively poor homology between the two gene clusters at the DNA sequence level.
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Department of Cell and Molecular Biology, Tulane University, New Orleans, Louisiana 70118.
Kendall
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D018528:ATP-Binding Cassette Transporters; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000235:genetics*; D005810:Multigene Family / Q000235:genetics*; D010641:Phenotype; D011487:Protein Conformation; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013302:Streptomyces / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; C058770:ChvA protein, Agrobacterium tumefaciens; D004268:DNA-Binding Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C079726:MsbA protein, Bacteria; C087734:RamA protein, Streptomyces coelicolor; C087735:RamB proteins, Streptomyces sp.; C087736:RamR protein, Streptomyces; D014157:Transcription Factors; C056783:ndvA protein, Rhizobium meliloti; C080370:UhpA protein, Bacteria