Signal sequence for generation of mRNA 3' end in the Saccharomyces cerevisiae GAL7 gene.

AUTOR(ES)

Abe, A

RESUMO

We have identified a signal sequence (designated core signal) necessary to specify formation of mRNA 3' end of the GAL7 gene in Saccharomyces cerevisiae within a DNA segment 26 bp long. The sequence was located 4-5 nucleotides upstream from the 3' end, i.e. the polyadenylation site, of the GAL7 mRNA. Replacement of a DNA segment encompassing the polyadenylation site with a pBR322 DNA, leaving the core signal intact, resulted in alteration of the mRNA 3' end by several nucleotides, suggesting the existence of an additional signal (designated end signal) at or near the polyadenylation site. The normal end formation was abolished when the core signal was placed in the reverse orientation. A considerable fraction of pre-mRNA synthesized in vitro with SP6 RNA polymerase on the template of a DNA fragment containing these signals was cleaved and polyadenylated presumably at the in vitro 3' end during incubation in a cell-free system of yeast. By contrast pre-mRNA synthesized on the template with the core signal alone was processed but much less efficiently. No such processing was seen when the pre-mRNA either lacked the core signal or contained it in the reverse orientation.

Documentos Relacionados

• Polymerase chain reaction mapping of yeast GAL7 mRNA polyadenylation sites demonstrates that 3' end processing in vitro faithfully reproduces the 3' ends observed in vivo.
• A complex unidirectional signal element mediates GCN4 mRNA 3' end formation in Saccharomyces cerevisiae.
• Duplicate upstream activating sequences in the promoter region of the Saccharomyces cerevisiae GAL7 gene.
• Saturation mutagenesis of a polyadenylation signal reveals a hexanucleotide element essential for mRNA 3' end formation in Saccharomyces cerevisiae.
• Expression of the Saccharomyces cerevisiae GAL7 gene on autonomous plasmids.