Affecting gene expression by altering the length and sequence of the 5' leader.

• DOI: 10.1073/pnas.81.24.7698
• Publication Date: 2006-05-31T09:34:50Z
• Authors: H Johansen; D Schümperli; M Rosenberg
• Keywords: Translational efficiency; Eukaryotic translation; Stop codon; Reading frame

We have utilized a recombinant vector system designed to study gene control elements by fusing them the Escherichia coli galactokinase (galK) examine effects of expression that result from introducing changes into 5' noncoding leader region galK transcription unit. varied length and found no effect on expression, provided initiation codon remained first AUG in Using synthetic linkers, we then inserted specific sequences, each containing single at defined position within region. inserts had widely different sequences surrounding codons determined magnitude these effects. In addition, placed upstream three possible translation reading frames so occurring terminates prior to, within, or downstream codon, respectively. Single-nucleotide frameshift mutations were also introduced one constructs shift other two frames. Depending upon where stopped relative observed consistently expression. Our results show an interferes with exerts its greatest when it translates out-of-frame through initiator gene. If is initiator, unexpectedly high level maintained.