A 38 nt region and its flanking sequences within gag of Friend murine leukemia virus are crucial for splicing at the correct 5' and 3' splice sites.
Microbiol Immunol
; 58(1): 38-50, 2014 Jan.
Article
em En
| MEDLINE
| ID: mdl-24236664
ABSTRACT
The genome of the Friend murine leukemia virus (Fr-MLV) contains a 5' splice site (5'ss) located at 205 nt and a 3'ss located at 5489 nt. In our previous studies, it was shown that if the HindIII-BglII (879-1904 bp) fragment within gag is deleted from the proA8m1 vector, which carries the entire Fr-MLV sequence, then cryptic splicing of env-mRNA occurs. Here, attempts were made to identify the genomic segment(s) in this region that is/are essential to correct splicing. First, vectors with a serially truncated HindIII-BglII fragment were constructed. The vector, in which a 38 bp fragment (1612-1649 bp) is deleted or reversed in proA8m1, only produced splice variants. It was found that a 38 nt region within gag contains important elements that positively regulate splicing at the correct splice sites. Further analyses of a series of vectors carrying the 38 bp fragment and its flanking sequences showed that a region (1183-1611 nt) upstream of the 38 nt fragment also contains sequences that positively or negatively influence splicing at the correct splice sites. The SphI-NdeI (5140-5400 bp) fragment just upstream of the 3'ss was deleted from vectors that carried the 38 bp fragment and its flanking sequences, which yielded correctly spliced mRNA; interestingly, these deleted vectors showed cryptic splicing. These findings suggest that the 5140-5400 nt region located just upstream of the 3'ss is required for the splicing function of the 38 nt fragment and its flanking sequences.
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MEDLINE
Assunto principal:
Genes gag
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Sequências Reguladoras de Ácido Nucleico
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Processamento Alternativo
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Sítios de Splice de RNA
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Vírus da Leucemia Murina de Friend
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article