Optimization of transgene expression in sugar-cane cells

Sugar-cane cells were transformed by electroporation using different geneti c constructs to analyze the influence of the octopine synthetase gene enhan cer (ocs) and the first intron-exon from rice act1 gene (a-E/I/E), upon gus A transgene expression. The quadruplicated ocs enhancer (4ocs) increased 6- fold the expression of the reporter gene. The introduction of the a-E/I/E i nto the transcriptional unit of the 4ocs/35S::gusA chimeric gene increased beta-glucuronidase (Gus) activity more than 69 times in transformed sugar-c ane cells. The lack of the 5'end of the a-E/I/E sequence led to a drastic d ecrease in the expression levels of the reporter gene.