Sequence analysis of rice rubi3 promoter gene expression cassettes for improved transgene expression

In a construct containing aGUS reporter gene driven by the 50 regulatory elements from rubi3, expression was enhanced 4-fold when a 20-nucleotide (nt) GUS 50 untranslated sequence was replaced with 9 nt sequences derived from rubi30s second exon. The roles of the sequences immediately upstream from the GUS translation initiation codon, and their significance in gene expression, were investigated. Sequence analysis suggests that complementarity between sequences immediately 50 of a translation initiation codon and the rice 17S rRNA may be responsible for the reduction in protein levels from constructs containing the GUS leader sequence. The results demonstrate an affect sequences immediately upstream from transgenic coding sequences have on expression, and when using the rubi3 50 regulatory sequence