In vivo HIV-1 frameshifting efficiency is directly related to the stability of the stem-loop stimulatory signal.
RNA
; 3(10): 1153-8, 1997 Oct.
Article
en En
| MEDLINE
| ID: mdl-9326490
In many retroviruses, the expression of reverse transcriptase, protease, and integrase is dependent upon a -1 frameshift event. The frameshift signal is composed of a slippery sequence where the ribosome shifts, and a downstream stimulatory sequence. In most cases, the stimulatory sequence is a pseudoknot, but in some viruses, such as human immunodeficiency virus type 1 (HIV-1), a single stem-loop is involved. Here, we analyzed the precise role of the stem-loop thermodynamic stability. We tested the frameshifting stimulatory activity of a series of HIV-1-derived sequences showing a stepwise increment of the estimated deltaG degrees. These sequences were introduced at the junction of a lacZ-luc fusion gene cloned on a versatile expression vector, and the different constructs were tested in Saccharomyces cerevisiae and in mouse NIH3T3 cells. The results showed that the frameshifting efficiency was correlated directly to the stem stability between deltaG degrees = -2.5 kcal mol(-1) and deltaG degrees = -19.4 kcal mol(-1). This demonstrates the essential role of the stability of the stem-loop and does not support the involvement of a specific RNA-binding protein target sequence. However, increasing further the stem stability led to a diminution of frameshifting efficiency, suggesting that the stem-loop acts through a precise kinetic of pausing. Because the same pattern was observed in both yeast and mouse cells, it is likely that the stimulatory mechanism is conserved through evolution.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
ARN Mensajero
/
ARN Viral
/
Regulación Viral de la Expresión Génica
/
VIH-1
/
Sistema de Lectura Ribosómico
Límite:
Animals
Idioma:
En
Revista:
RNA
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
1997
Tipo del documento:
Article
País de afiliación:
Francia
Pais de publicación:
Estados Unidos