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FUNCTIONAL CHARACTERIZATION OF THE NOVEL GENE CIA7 FROM CHLAMYDOMONAS REINHARDTII
Author(s) -
Cantu Hector Guillermo Gonzalez,
Ynalvez Ruby Agno
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.665.6
Subject(s) - chlamydomonas reinhardtii , biochemistry , biology , mutant , gene , bioaccumulation , chemistry , microbiology and biotechnology , environmental chemistry
Heavy metal contamination presents a constant threat to biological systems. These metals interact with the catalytic‐domain of enzymes, interfering with their normal rates of activity, as well as inducing oxidative stress. Certain microorganisms have evolved molecular mechanisms to attenuate this; one of them being the expression and synthesis of low‐molecular weight, thiol‐rich proteins, termed as phytochelatins and metallothioneins. One such organism is Chlamydomonas reinhardtii . C. reinhardtii is an excellent model organism used in studies of heavy metals due to its high endogenous tolerance. In C. reinhardtii a novel gene designated as Cia7, was isolated and was hypothesized to confer tolerance to heavy metals. This was due to CIA7's conserved Cys‐residue motif. Such motif is found in a number of metal binding proteins. In this regard, this study aimed to demonstrate what role, if any, CIA7 exerts on tolerance towards Cd 2+ stress in C. reinhardtii. The hypothesis was that the expression of Cia7 will contribute, at least in part, to an increased Cd‐tolerance in C. reinhardtii , as evidenced by physiological markers of health, as well as intracellular accumulation of the metal. The discovery of gene Cia7 in C. reinhardtii may lead to the elucidation of a novel mechanism of metal tolerance or homeostasis in C. reinhardtii . To functionally characterize Cia7: (1) comparative studies of chlorophyll fluorescence and cell size in WT and cia7 − in the presence of Cd 2+ , (2) comparative studies of Cd 2+ bioaccumulation in WT and cia7 − , and (3) Cd 2+ tolerance assays in cia7 insertional mutants were designed. The present work reports on the findings of Cd 2+ induced decreased chlorophyll fluorescence and cell size in the cia7 − mutant, as well as no difference in Cd‐bioaccumulation at low (5, 10μM) Cd 2+ concentrations amongst the WT and cia7 − . These results indicate a possible correlation amongst cia7 expression and Cd 2+ tolerance. The characterization of CIA7 as a metal‐binding protein would allow for its potential usage as a metal sequestering agent in environmental applications. This would facilitate the remediation of metal‐contaminated ecosystems, which would eliminate the risk of metal poisoning in humans. Furthermore, a correlation of heavy metal exposure to cia7 expression could designate CIA7 as a biomarker for heavy metal contamination. Support or Funding Information College of Arts and Sciences and Office of Graduate Studies This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .