Focal altered compartmentation of repetitive B2 (Alu-like) sequences in rat liver following hepatocarcinogen exposure.
Cell Growth Differ
; 7(5): 635-46, 1996 May.
Article
en En
| MEDLINE
| ID: mdl-8732673
Rats were treated with low doses of the hepatocarcinogens dimethylnitrosamine or thioacetamide, and livers were examined 48 h later. These treatments are known to produce altered RNA compartmentation, wherein a class of repetitive RNA sequences normally restricted to the nucleus appears in the cytoplasm. Reverse transcription-PCR amplifications demonstrated that the sequences showing altered compartmentation consisted largely of a subfamily of the rodent B2 sequence family, the counterpart of human Alu sequences involved in retrotransposition. Northern blot analyses showed that these B2 sequences were found in cytoplasmic RNA as 170- to 360-nucleotide "sense" transcripts, and competition hybridization experiments established that B2 sequences represented most (if not all) of the sequences showing altered compartmentation. The major increase in B2 transcriptions in cytoplasmic RNA was not associated with any change in B2 transcription by RNA polymerase III. In situ hybridizations showed that the altered compartmentation of B2 sequences occurred in well-delineated foci within the rat liver; these foci consisted of a central region containing a prominent infiltrate of macrophages admixed with small hepatocytes and a peripheral region of histologically normal hepatocytes that showed evidence of oxidative damage. Altered compartmentation of B2 sequences may represent an important focal initiatory change in a subset of hepatocytes, whereas subsequent retrotranspositional events (associated with Alu-like sequences) could predispose initiated cell foci to alterations in promotion/progression phases.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
ARN Mensajero
/
Secuencias Repetitivas de Ácidos Nucleicos
/
Compartimento Celular
/
Carcinoma Hepatocelular
/
Neoplasias Hepáticas
Límite:
Animals
Idioma:
En
Revista:
Cell Growth Differ
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
1996
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos