In this research, important stress and redox regulatory genes present in
Hydra vulgaris were isolated and characterized to facilitate our understanding of
the evolution and mechanisms of stress response. H. vulgaris heat shock protein
70 (HvHSP70), extracellular copper zinc superoxide dismutase (HvECCuZnSOD),
manganese superoxide dismutase (HvMnSOD), phospholipid
peroxidase glutathione peroxidase (HvPHGPx) and monofunctional catalase
(HvCatalase) were cloned and characterized with regard to stress response,
phylogeny and molecular structure.
The HSP70 gene isolated from H. vulgaris encodes a polypeptide of 650
amino acids (Mw=710,037) and is interrupted by three intron sequences. The 5'
non-coding region of the HvHSP70 possessed the canonical heat shock
elements. Phylogenetically HvHSP70 formed a distinct lineage. A molecular
model generated for the N-terminal fragment of the HvHSP70 displayed the heat
shock protein fold and domains of phosphotransferases. The EC-CuZnSOD cDNA isolated from H. vulgaris encodes a protein of
189 amino acids (Mw=20959.73); the first 19 amino acids constitute the
presumed signal peptide. Phylogenetically HvEC-CuZnSOD is grouped with ECCuZnSODs
from several organisms. A molecular model generated for the
HvEC-CuZnSOD displayed the CuZnSOD (beta)-barrel fold.
The MnSOD cDNA isolated from H. vulgaris encodes a protein of 219
amino acids (Mw=24348.75); the first 21 amino acids constitute the presumed
mitochondria-targeting signal peptide. Phylogenetically HvMnSOD is clustered
with mollusk and crustacean MnSODs. A molecular model generated for the
HvMnSOD displayed the N-terminal long alpha antiparallel hairpin and the Cterminal
mixed alpha/beta fold characteristic of MnSODs.
The PHGPx gene isolated from H. vulgaris encodes a polypeptide of 168
amino acids (Mw=18746.51) including a TGA-encoded selenocysteine at residue
44 and lacks any intron. Phylogenetically HvPHGPx is grouped with PHGPxs
from several organisms. A molecular model generated for the HvPHGPx
displayed the thioredoxin fold.
The 3'-end of a cDNA sequence encoding for 168 amino acids of the Cterminal
end of a catalase was isolated from H. vulgaris. Phylogenetically
HvCatalase is grouped with heme-containing monofunctional catalases.
Hydrae exposed to thermal, starvation, oxidative and metal stress
responded by regulating respective mRNA transcriptions suggesting that these genes are involved in stress and (anti)oxidative processes and may have
potential as molecular biomarkers for assessing aquatic environment quality.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4994 |
| Date | 25 April 2007 |
| Creators | Dash, Bhagirathi |
| Contributors | Phillips, Timothy D. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 3859433 bytes, electronic, application/pdf, born digital |
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