The two genes encoding yeast ribosomal protein S8 reside on different chromosomes, and are closely linked to the hsp70 stress protein genes SSA3 and SSA4

5' untranslated regions: the next regulatory sequence in yeast synthetic biology

When developing industrial biotechnology processes, Saccharomyces cerevisiae (baker's yeast or brewer's yeast) is a popular choice as a microbial host. Many tools have been developed in the fields of synthetic biology and metabolic engineering to introduce heterologous pathways and tune their expression in yeast. Such tools mainly focus on controlling transcription, whereas post-transcriptional regulation is often overlooked. Herein we discuss regulatory elements found in the 5' untranslated region (UTR) and their influence on protein synthesis. We provide not only an overall picture, but also a set of design rules on how to engineer a 5' UTR. The reader is also referred to currently available models that allow gene expression to be tuned predictably using different 5' UTRs.

Kluyveromyces lactis SEF1 and its Saccharomyces cerevisiae homologue bypass the unknown essential function, but not the mitochondrial RNase P function, of the S. cerevisiae RPM2 gene

RPM2 is a Saccharomyces cerevisiae nuclear gene required for normal cell growth yet the only known function of Rpm2p is as a protein subunit of yeast mitochondrial RNase P, an enzyme responsible for the 5' maturation of mitochondrial tRNAs. Since mitochondrial protein synthesis in S. cerevisiae is not essential for viability, RPM2 must provide another function in addition to its known role as a mitochondrial tRNA processing enzyme. During a search for RPM2 homologues from Kluyveromyces lactis, we recovered a K. lactis gene that compensates for the essential function but not the RNase P function of RPM2. We have named this gene SEF1 (Suppressor of the Essential Function), DNA sequence analysis of SEF1 reveals it contains a Zn(2)-Cys(6) binuclear cluster motif found in a growing number of yeast transcription factors. The SEF1 homologue of S. cerevisiae also compensates for the essential function of RPM2. The two proteins share 49% identity and 72% amino acid sequence similarity.

Sequence, map position and genome organization of the RPL17B gene, encoding ribosomal protein L17b in Saccharomyces cerevisiae

Sequence analysis of the newly defined SSU81 gene revealed an adjacent open reading frame (ORF) encoding a protein whose deduced amino acid sequence is identical to that of ribosomal protein L17. The DNA sequence of this region is different from that of the RPL17A gene and therefore represents a duplicate gene encoding L17. We have designated this gene RPL17B. The RPL17B coding region is split by an intron that occurs in the same position (codons 14/15) as the intron in RPL17A. The RPL17B promoter region includes two TATA boxes, a canonical UASRPG motif, and several pyrimidine-rich tracts. RPL17B was mapped by CHEF and lambda clone grid hybridization blots to the right arm of chromosome V, linked to the TRP2 and RAD51 genes. A partial ORF was identified adjacent to RPL17B and SSU81 that is homologous to an ORF (designated A509) physically linked to RPL17A. This observation, and the identical position of the introns within the RPL17 genes, suggest that one RPL17 locus arose by duplication and translocation of the other.