Abstract:

In this paper, promoter fragments of four genes, lactate dehydrogenase A (ldhA), pyruvate decarboxylase A (pdcA),
glucoamylase A (amyA) and phosphoglycerate kinase 1 (pgk1), from genome DNA of Rhizopus oryzae strain AS 3.819,
were amplified and screened in Escherichia coli strain JM109 by using promoter probe vector pUKMR containing β-lactamase
gene (bla) as its reporter gene. The results suggested that the four promoter fragments all possessed the ability to drive the
expression of the β-lactamase gene. The promoters of ldhA and pgk1 genes possessed high promoting strength even though
no inducing substrate was present, while the strength of pdcA and amyA promoters could be enhanced when the suitable
carbon source was adopted. The strength of ldhA promoter was enhanced as the fragment length increased until it reached
500 bp. This research provides a quick and easy method to isolate and detect gene promoters form Rhizopus oryzae.

Key words: Rhizopus oryzae, Escherichia coli, promoter probe vector, β-lactamase, lactate dehydrogenase