The Israeli Journal of Aquaculture - Bamidgeh 55(4), 2003
The 7th Annual Dan Popper Symposium
ISOLATION OF A PROMOTER WITH HIGH EXPRESSION
ACTIVITY FROM THE RED MICROALGA PORPHYRIDIUM SP.
Lena Plesser¹, ², Miri Lapidot¹, Yacob Weinstein³ and Shoshana (Malis) Arad¹ *
1 The Institute for Applied Biosciences, Ben Gurion University of the Negev, Beer Sheva, Israel
2 Department of Biotechnology Engineering, Faculty of Engineering Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel
3 Department of Microbiology and Immunology, Faculty of Health Sciences,
Ben Gurion University of the Negev, Beer Sheva, Israel
Red microalgae constitute a valuable resource that will find application in a range of biotechnological
products such as pigments, unsaturated fatty acids and sulfated polysaccharides.
However, the lack of basic molecular tools, such as mutants, genomic libraries and transformation
systems, is currently limiting the biotechnological exploitation of these microorganisms. Our
group recently developed a novel chloroplast transformation system with the AHAS gene as a
selectable marker for sulfometuron methyl (SMM) resistance. We also established an expressed
sequence tag (EST) project that contains cDNA libraries obtained from red microalgae grown
under different physiological conditions. As a tool for biotechnological exploitation, we sought an
endogenous promoter that would give a high level of foreign protein expression in the algal cells.
To this end, we cloned a homologous promoter of the actin depolymerization factor (ADF) gene,
which had been found to be highly expressed in various cDNA libraries of the red microalga
Porphyridium sp. With the inverse PCR method, we isolated a 1.1-kb fragment containing the
promoter of the ADF gene. The promoter contains the TATA box and GC box and can be used
for the construction of red microalgae expression vector. Characterization of additional promoters