Relationship between G+C content, ORF-length and mRNA concentration in Saccharomyces cerevisiae

RNA biogenesis is a tightly-regulated process. The levels and timing of expression of a gene depends on its particular function. However, gene expression levels may also depend on structural features. Here we describe the analysis of gene expression of 4977 ORFs using DNA microarrays covering the whole genome of three different S. cerevisiae strains, wild-type and tho2 and thp1 mutants with a general effect on mRNA biogenesis. We show that transcripts from G+C-rich ORFs accumulate at higher concentrations than those from G+C-poor ones, in different ORF-length categories in all strains tested. In addition, we found a negative correlation between ORF length and G+C content. Our results indicate that length and G+C content of a gene have a clear effect on its levels of expression. We discuss the biological relevance of these results, as well as different ways that these structural features could modulate mRNA biogenesis.