PRP4: a protein of the yeast U4/U6 small nuclear ribonucleoprotein particle

An essential gene in Saccharomyces cerevisiae shares an upstream regulatory element with PRP4

ORF2 is an essential gene immediately upstream of PRP4 (formerly RNA4), a gene involved in nuclear mRNA processing in Saccharomyces cerevisiae. The two genes are arranged head-to-head. An 8 base-pair conserved sequence element is found upstream of both genes, as well as upstream of certain other genes that are known to be involved in pre-mRNA processing. Through deletion analysis we have found that both of the conserved sequence elements are important for transcription of both genes. We have cloned ORF2 and have isolated temperature-sensitive orf2 mutants. The phenotype of these mutants does not suggest a role for ORF2 in mRNA processing. The deduced amino acid sequence of ORF2 indicates significant similarity to DPR1, a gene encoding a protein that is involved in the carboxy-terminal processing of G-protein.

Splicing stories and poly(A) tales: an update on RNA processing and transport

The basic steps in RNA processing, transport and translation have been conserved throughout eukaryotic evolution, as have many of the components involved. Nevertheless, the recognition processes which underlie RNA metabolism also display non-conserved features, whose appearance may have been made necessary by the increasing number and variety of processing substrates in higher eukaryotes and the complex requirements for differential regulation of RNA metabolism. Although many components of the mRNA processing machinery have been identified, our understanding of how a precursor is defined and accurately processed is still rudimentary. There are numerous indications that gene expression, from transcription all the way through to translation, is an integrated process. The challenge is to understand RNA processing and transport within this integrated whole.