RT Journal Article SR Electronic(1) A1 Servn-Gonzlez, Luis A1 Sampieri, Arstides A1 Cabello, Javier A1 Galvn, Lilia A1 Jurez, Vctor A1 Castro, ClementinaYR 1995 T1 Sequence and functional analysis of the Streptomyces phaeochromogenes plasmid pJV1 reveals a modular organization of Streptomyces plasmids that replicate by rolling circle JF Microbiology, VO 141 IS 10 SP 2499 OP 2510 DO https://doi.org/10.1099/13500872-141-10-2499 PB Microbiology Society, SN 1465-2080, AB Summary: pJV1 is an 11 kb, high-copy-number conjugative Streptomyces phaeochromogenes plasmid that replicates by the rolling circle mechanism (RCR). Sequencing combined with functional analysis of deletion, insertion and frameshift mutations was used to characterize the genes involved in plasmid transfer and chromosome mobilization (Cma), the single-strand origin for RCR and an associated strong incompatibility (Sti) determinant. pJV1 contains two essential transfer genes whose expression is regulated by an adjacent repressor gene with similarity to the GntR family of regulators. A consensus sequence specific for the helix-turn-helix motifs of repressor proteins of Streptomyces plasmids is proposed. Unregulated expression of the transfer genes by inactivation of the repressor is lethal. Three additional genes increase intramycelial plasmid spread resulting in pock formation but, unlike the essential transfer genes, are not required for Cma. The pJV1 transfer genes and their regulatory region, but not the minimal replication region encoding the double-strand replication origin and replication protein, are similar in their sequence and arrangement to those of the Streptomyces nigrifaciens plasmid pSN22, revealing a modular organization of Streptomyces RCR plasmids., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/13500872-141-10-2499