z-logo
open-access-imgOpen Access
Role of an upstream open reading frame in mediating arginine-specific translational control in Neurospora crassa
Author(s) -
Zongli Luo,
Matthew S. Sachs
Publication year - 1996
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.178.8.2172-2177.1996
Subject(s) - biology , upstream open reading frame , open reading frame , five prime untranslated region , genetics , translation (biology) , gene , start codon , citrullinemia , neurospora crassa , translational regulation , mutant , messenger rna , arginine , peptide sequence , amino acid , citrulline
The Neurospora crassa arg-2 transcript contains an upstream open reading frame (uORF) specifying a 24-residue leader peptide and is subject to a novel form of negative translational regulation in response to arginine. The role of the arg-2 uORF in arginine-specific negative regulation was investigated by using translational fusions of wild-type and mutant arg-2 sequences to the Escherichia coli lacZ reporter gene specifying beta-galactosidase. The wild-type uORF conferred Arg-specific regulation on the reporter gene in N. crassa, but mutated or truncated uORFs did not, as determined by measurements of beta-galactosidase activity produced in N. crassa strains expressing arg-2-lacZ fusion genes. All effects on reporter gene expression were posttranscriptional, as determined by measurement of RNA levels. Both sequence-dependent and sequence-independent effects of uORFs were observed. Genes containing the wild-type uORF or a 21-codon mutated uORF showed reduced translation in comparison with that of a gene lacking a uORF. Both uORF-containing transcripts showed reduced association with polysomes relative to transcripts lacking a uORF, but only the transcript with the wild-type uORF showed a reduced average number of ribosomes associated with it in response to arginine addition. Direct translational fusions between uORF sequences and lacZ sequences indicated that the uORF is translated. Overlapping the uORF with the lacZ initiation codon indicated that ribosome reinitiation at a downstream start codon is not integral to uORF-mediated, Arg-specific translational regulation. These studies provide direct biochemical evidence for arg-2 uORF function in translational control.

The content you want is available to Zendy users.

Already have an account? Click here to sign in.
Having issues? You can contact us here