The promoters of the genes for colicin production, release and immunity in the ColA plasmid: effects of convergent transcription and Lex A protein.
Nucleic Acids Res
; 14(6): 2621-36, 1986 Mar 25.
Article
em En
| MEDLINE
| ID: mdl-2421251
ABSTRACT
The initiation sites of transcription in vivo for the three genes caa, cai and cal encoding respectively colicin A (Caa), the immunity protein (Cai) and the pColA lysis protein (Cal) have been analysed by nuclease S1 mapping. This analysis demonstrates that caa and cal form an operon. cai is located between these two genes and transcribed in the opposite direction from its own promoter. The start sites for caa and cai have also been determined in vitro. For caa, the same start site was found in vivo and in vitro. In contrast, for cai the most efficient start site in vitro was not used in vivo. LexA protein strongly repressed the in vivo and in vitro transcription of the caa-cal operon. As determined by DNase 1 protection experiments, LexA protein binds with a high affinity to an approximately 40 bp long sequence just downstream of the Pribnow box. The sequence of the binding site is composed of two overlapped "SOS boxes". Two transcripts of the caa-cal operon were detected by blot hybridization. The longer mRNA can direct the synthesis of both Caa and Cal while the shorter one is terminated at the end of caa. When the transcription of the caa-cal operon is induced, there is a strong interference with cai transcription.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Plasmídeos
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Serina Endopeptidases
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Regiões Promotoras Genéticas
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Plasmídeos de Bacteriocinas
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Colicinas
Idioma:
En
Revista:
Nucleic Acids Res
Ano de publicação:
1986
Tipo de documento:
Article