Elimination of introns at the Drosophila suppressor-of-forked locus by P-element-mediated gene conversion shows that an RNA lacking a stop codon is dispensable.
The suppressor of forked [su(f)] locus affects the phenotype of mutations caused by transposable element insertions at unlinked loci. It encodes a putative 84-kD protein with homology to two proteins involved in mRNA 3' end processing; the product of the yeast RNA14 gene and the 77-kD subunit of human cleavage stimulation factor. Three su(f) mRNAs are produced by alternative polyadenylation. The 2.6- and 2.9-kb mRNAs encode the same 84-kD protein while a 1.3-kb RNA, which terminates within the fourth intron, is unusual in having no stop codon. Using P-element-mediated gene replacement we have copied sequences from a transformation construct into the su(f) gene creating a su(f) allele at the normal genomic location that lacks the first five introns. This allele is viable and appears wild type for su(f) function, demonstrating that the 1.3-kb RNA and the sequences contained within the deleted introns are dispensable for su(f) function. Compared with studies on gene replacement at the white locus, chromosomal breaks at su(f) appear to be less efficiently repaired from ectopic sites, perhaps because of the location of su(f) at the euchromatin/heterochromatin boundary on the X chromosome.
Williams
C J
CJ
Department of Biochemistry, Imperial College of Science, Technology and Medicine, London, United Kingdom.
O'Hare
K
K
D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D003062:Codon; D003433:Crosses, Genetic; D017931:DNA Primers; D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D005785:Gene Conversion; D017344:Genes, Insect; D006801:Humans; D007301:Insect Hormones / Q000235:genetics; D007438:Introns; D008297:Male; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D014170:Transformation, Genetic
D003062:Codon; D017931:DNA Primers; D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D007301:Insect Hormones; D009687:Nuclear Proteins; D011506:Proteins; D012333:RNA, Messenger; C079745:su(f) protein, Drosophila