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Identification of a new gene in the streptococcal plasmid pLS1: the rnaI gene.
Plasmid 1998; 40(3):214-24P

Abstract

The streptococcal plasmid pMV158 has been reported to harbor five genes: three involved in initiation of rolling circle replication and its control (copG, repB, and maII), one involved in conjugative mobilization (mobM), and the fifth one specifying constitutive resistance to tetracycline (tet). The mobM gene was removed in the construction of the pMV158-derivative plasmid pLS1, which was used in this study. By in vitro transcription assays, primer extension experiments, and construction of mutations, here we demonstrate the presence of another gene (the sixth of pMV158), termed maI, which is transcribed in opposite orientation with respect to the plasmid mRNAs, to render RNA I. The 5'-end of RNA I has an 8-nt sequence which is complementary to a region of the lagging-strand origin (ssoA) comprising a 6-nt consensus sequence involved in lagging strand synthesis. This suggested that RNA I could influence, positively or negatively, initiation of lagging strand synthesis from the pLS1-ssoA. However, plasmids defective in RNA I synthesis exhibited a phenotype similar to the wild type in terms of efficiency of replication from the ssoA and copy number. When the maI gene was cloned into a compatible plasmid, the resulting recombinants did not exhibit incompatibility toward plasmids with the pLS1 replicon. Thus, RNA I does not seem to be a true copy number control element. We postulate that transcription from the maI promoter may facilitate extrusion of the hairpin of the plasmid double-strand origin, which is the target of the initiator of replication protein.

Authors+Show Affiliations

Centro de Investigaciones Biológicas, CSIC, Velázquez, 144, Madrid, E-28006, Spain.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

9806858

Citation

Acebo, P, et al. "Identification of a New Gene in the Streptococcal Plasmid pLS1: the rnaI Gene." Plasmid, vol. 40, no. 3, 1998, pp. 214-24.
Acebo P, Hernández-Arriaga AM, Kramer MG, et al. Identification of a new gene in the streptococcal plasmid pLS1: the rnaI gene. Plasmid. 1998;40(3):214-24.
Acebo, P., Hernández-Arriaga, A. M., Kramer, M. G., Espinosa, M., & del Solar, G. (1998). Identification of a new gene in the streptococcal plasmid pLS1: the rnaI gene. Plasmid, 40(3), pp. 214-24.
Acebo P, et al. Identification of a New Gene in the Streptococcal Plasmid pLS1: the rnaI Gene. Plasmid. 1998;40(3):214-24. PubMed PMID: 9806858.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Identification of a new gene in the streptococcal plasmid pLS1: the rnaI gene. AU - Acebo,P, AU - Hernández-Arriaga,A M, AU - Kramer,M G, AU - Espinosa,M, AU - del Solar,G, PY - 1998/11/10/pubmed PY - 1998/11/10/medline PY - 1998/11/10/entrez SP - 214 EP - 24 JF - Plasmid JO - Plasmid VL - 40 IS - 3 N2 - The streptococcal plasmid pMV158 has been reported to harbor five genes: three involved in initiation of rolling circle replication and its control (copG, repB, and maII), one involved in conjugative mobilization (mobM), and the fifth one specifying constitutive resistance to tetracycline (tet). The mobM gene was removed in the construction of the pMV158-derivative plasmid pLS1, which was used in this study. By in vitro transcription assays, primer extension experiments, and construction of mutations, here we demonstrate the presence of another gene (the sixth of pMV158), termed maI, which is transcribed in opposite orientation with respect to the plasmid mRNAs, to render RNA I. The 5'-end of RNA I has an 8-nt sequence which is complementary to a region of the lagging-strand origin (ssoA) comprising a 6-nt consensus sequence involved in lagging strand synthesis. This suggested that RNA I could influence, positively or negatively, initiation of lagging strand synthesis from the pLS1-ssoA. However, plasmids defective in RNA I synthesis exhibited a phenotype similar to the wild type in terms of efficiency of replication from the ssoA and copy number. When the maI gene was cloned into a compatible plasmid, the resulting recombinants did not exhibit incompatibility toward plasmids with the pLS1 replicon. Thus, RNA I does not seem to be a true copy number control element. We postulate that transcription from the maI promoter may facilitate extrusion of the hairpin of the plasmid double-strand origin, which is the target of the initiator of replication protein. SN - 0147-619X UR - https://www.unboundmedicine.com/medline/citation/9806858/Identification_of_a_new_gene_in_the_streptococcal_plasmid_pLS1:_the_rnaI_gene_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0147-619X(98)91370-1 DB - PRIME DP - Unbound Medicine ER -