Journal
GENE
Volume 379, Issue -, Pages 156-165Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.gene.2006.05.004
Keywords
cadmium; gene expression; development; metal-responsive element
Categories
Ask authors/readers for more resources
Metallothioneins (MTs) are typically low molecular weight (6-7 kDa), metal-binding proteins with characteristic repeating cysteine motifs (Cys-X-Cys or Cys-X-n-Cys) and a prolate ellipsoid shape containing single alpha- and beta-domains. While functionally diverse, they play important roles in metals homeostasis, detoxification and the stress response. The present study, combined with previous observations (e.g., Jenny et al., Eur. J. Biochem. 2005; 271:1702-1712) defines an unprecedented diversity of MT primary structure and domain organization in the American oyster, Crassostrea virginica. Two novel molluscan MT families are described. One of these (CvMT-III) is characterized by the presence of two beta-domains and the absence of a-domains. This family exhibits constitutive expression during larval development and is the dominant CvMT isoform expressed in larvae. CvMT-III displays low basal levels of expression in adult tissues and only moderate responsiveness to metal challenges in both larvae and adults. A second novel MT isoform (CvMT-IV) was isolated from hemocytes by subtractive hybridization techniques following a 4-hour immune challenge with heat-killed bacteria Vibrio, Bacillus, Micrococcus spp. mixture). Based on conservation of the cysteine motifs, this isoform appears to be a sub-family related to the molluscan alpha beta-domain MTs. A series of amino acid substitutions has resulted in four additional cysteines which give rise to a Cys-Cys motif and three Cys-Cys-Cys motifs. Northern blot analyses demonstrate that CvMT-IV is down-regulated upon sterile wounding and immune challenge, displays moderate expression in larvae and adults and differential gene induction in response to metals exposure. (c) 2006 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available