Direct repeat sequences are essential for function of the cis-acting locus of transfer (clt) of Streptomyces phaeochromogenes plasmid pJV1.
The functionality of direct and inverted repeat sequences inside the cis acting locus of transfer (clt) of the Streptomyces plasmid pJV1 was determined by testing the effect of different deletions on plasmid transfer. The results show that the single most important element for pJV1 clt function is a series of evenly spaced 9 bp long direct repeats which match the consensus CCGCACA(C/G)(C/G), since their deletion caused a dramatic reduction in plasmid transfer. The presence of these repeats in the absence of any other clt sequences allowed plasmid transfer to occur at a frequency that was at least two orders of magnitude higher than that obtained in the complete absence of clt. A database search revealed regions with a similar organization, and in the same position, in Streptomyces plasmids pSN22 and pSLS, which have transfer proteins homologous to those of pJV1.
Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apartado Postal 70228, Ciudad Universitaria, DF 04510, Mexico.
Bernardo
B
Franco
Gabriela
G
González-Cerón
Luis
L
Servín-González
D001483:Base Sequence; D003227:Conjugation, Genetic; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D021901:DNA, Intergenic; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid; D012091:Repetitive Sequences, Nucleic Acid; D017384:Sequence Deletion; D013302:Streptomyces / Q000235:genetics*
D004269:DNA, Bacterial; D021901:DNA, Intergenic