Functional promoter elements common to ribosomal protein and ribosomal RNA genes in Neurospora crassa

Abstract

 The promoter sequences of a cytoplasmic ribosomal protein gene (crp-2) of Neurospora crassa were identified using promoter deletion and substitution mutants. A gene-targeting strategy was used to assay the mutants in vivo. The promoter architecture of crp-2 is complex and is more similar to that of ribosomal protein genes in mouse than in Saccharomyces cerevisiae. Six regions were identified as important for transcription. These included two elements, a CG repeat and a Dde box, that are conserved in most other promoters of N. crassa ribosomal protein genes and have also been demonstrated as being required for transcription from the 40 S rRNA promoter by RNA polymerase I in vitro. The CG repeats located at −73 to −66 and between −189 and −154 were functionally redundant and increased transcription efficiency by 10- to 15- fold. The Dde boxes located at −153 to −147 and at −95 to −83 contributed 2-fold and 5-fold to transcription efficiency, respectively. An unidentified element between −254 and −190 contributed 2-fold, while a pyrimidine-rich region between −85 and −66 influenced the start point of transcription.