The effect of toxic heavy metals, Hg and Cd on the mRNA expression levels of the novel gene CIA7 of Chlamydomonas reinhardtii (995.4)

Abstract

Heavy metal pollution of the environment is a growing concern to biological researchers due to its potentially harmful effects. Bioremediation of these toxic metals by species of algae has been researched as a possible alternative. Chlamydomonas reinhardtii contain a novel gene: CIA7of unclear function. Due to its possession of conserved cysteine amino‐acid residues, this gene is hypothesized to play a role in the binding and tolerance of heavy metals.This study aims to qualitatively assess the levels of mRNA expression obtained from two strains of C. reinhardtii upon exposure to sub‐lethal levels of Hg and Cd. The two strains referred to are a wild‐type (D66) and a mutant strain (cia7) of C. reinhardtii. The mutant was isolated from inorganic carbon acquisition mutants. Upregulation of the CIA7 gene following a toxic metal treatment will provide a basis for CIA7’s role in heavy metal tolerance.To perform the expression analysis of the CIA7 gene, D66 and cia7 algal strains were exposed to sub‐lethal concentrations of Hg and Cd in liquid media. A separate control treatment with no heavy metal content was also performed. After an exposure time of three hours, total RNA was extracted and purified. The entire RNA content of the algae was then converted into its complementary DNA (cDNA). Amplification of the CIA7 gene was performed using the polymerase chain reaction and the band intensities were compared using Quantity One analysis software. The comparison in expression levels between both algal strains and between metal treatments will help determine whether CIA7 has the potential for abatement of toxic heavy metals.Grant Funding Source: Supported by: Norman Hackerman Advanced Research Program