Sequence requirements for terminators and antiterminators in the T box transcription antitermination system: disparity between conservation and functional requirements.
Nucleic Acids Res
; 30(7): 1646-55, 2002 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-11917026
ABSTRACT
The T box transcription termination control system is used in Gram-positive bacteria to regulate expression of aminoacyl-tRNA synthetase and other amino acid-related genes. Readthrough of a transcriptional terminator located in the leader region of the target gene is dependent on a specific interaction between the nascent leader transcript and the cognate uncharged tRNA. This interaction is required for formation of an antiterminator structure in the leader, which prevents formation of a competing transcriptional terminator stem-loop. The antiterminators and terminators of genes in this family are highly conserved in both secondary structure and primary sequence; the antiterminator contains the T box sequence, which is the most highly conserved leader element. These conserved features were investigated by phylogenetic and mutational analysis. Changes at highly conserved positions in the bulge and in the helix above the bulge reduced function, while alteration of other positions that were as much as 96% conserved did not have a major effect. The disparity between sequence conservation and function may be due to the requirement for maintaining base pairing in both the antiterminator and terminator structures.
Texto completo:
1
Temas:
ECOS
/
Equidade_desigualdade
Bases de dados:
MEDLINE
Assunto principal:
Transcrição Gênica
/
Regiões Terminadoras Genéticas
Aspecto:
Equity_inequality
Idioma:
En
Revista:
Nucleic Acids Res
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos