Drosophila 5 S RNA processing requires the 1-118 base pair and additional sequence proximal to the processing site.
Using an in vitro processing system, we have identified a required sequence surrounding the Drosophila melanogaster 5 S RNA processing site at nucleotide 120. Mutations in this region vary the processing rate from complete inhibition to a level equal to or greater than wild type. Analysis of mutants at +1 and in the region 118-122 separates the inhibitory effect into two parts. 1) Nucleotide 118 C, the base-paired nucleotide in helix I proximal to the processing site, plays an essential role. Changing it to a purine inhibits processing. The +1-118 base pair must be intact, but this alone is not sufficient for processing, since compensatory changes at +1 do not restore down-processing mutants at 118 to the wild type level. 2) The processing site has to be pyrimidine rich; multiple contiguous purines inhibit processing. On the other hand, multiple pyrimidines can largely negate the inhibitory effect of a mutation at position 118. Thus a base-paired C at 118 followed by a stretch of pyrimidines is the processing signal, which may be recognized by the processing enzyme and/or a required accessory factor.
Preiser
P R
PR
School of Life and Health Sciences, University of Delaware, Newark 19716.
Levinger
L F
LF
D000818:Animals; D001482:Base Composition; D001483:Base Sequence; D002478:Cells, Cultured; D002678:Chimera; D002872:Chromosome Deletion; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics*; D005796:Genes; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis; D010957:Plasmids; D012341:RNA, Ribosomal, 5S / Q000235:genetics*; D013604:T-Phages / Q000201:enzymology; D014158:Transcription, Genetic
D009838:Oligodeoxyribonucleotides; D012341:RNA, Ribosomal, 5S; D012321:DNA-Directed RNA Polymerases