PUBLICATION
Gene duplication and separation of functions in alphaB-crystallin from zebrafish (Danio rerio)
- Authors
- Smith, A.A., Wyatt, K., Vacha, J., Vihtelic, T.S., Samuel Zigler, J. Jr, Wistow, G.J., and Posner, M.
- ID
- ZDB-PUB-060124-23
- Date
- 2006
- Source
- The FEBS journal 273(3): 481-490 (Journal)
- Registered Authors
- Posner, Mason, Vihtelic, Thomas
- Keywords
- none
- MeSH Terms
-
- Alternative Splicing*
- Amino Acid Sequence
- Animals
- Cloning, Molecular
- Electrophoresis, Gel, Two-Dimensional
- Electrophoresis, Polyacrylamide Gel
- Gene Duplication*
- Gene Expression Regulation
- Humans
- Molecular Sequence Data
- Phylogeny
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Alignment
- Temperature
- Time Factors
- Zebrafish/genetics*
- alpha-Crystallin B Chain/genetics*
- alpha-Crystallin B Chain/physiology*
- PubMed
- 16420472 Full text @ FEBS J.
Citation
Smith, A.A., Wyatt, K., Vacha, J., Vihtelic, T.S., Samuel Zigler, J. Jr, Wistow, G.J., and Posner, M. (2006) Gene duplication and separation of functions in alphaB-crystallin from zebrafish (Danio rerio). The FEBS journal. 273(3):481-490.
Abstract
We previously reported that zebrafish alphaB-crystallin is not constitutively expressed in nervous or muscular tissue and has reduced chaperone-like activity compared with its human ortholog. Here we characterize the tissue expression pattern and chaperone-like activity of a second zebrafish alphaB-crystallin. Expressed sequence tag analysis of adult zebrafish lens revealed the presence of a novel alpha-crystallin transcript designated cryab2 and the resulting protein alphaB2-crystallin. The deduced protein sequence was 58.2% and 50.3% identical with human alphaB-crystallin and zebrafish alphaB1-crystallin, respectively. RT-PCR showed that alphaB2-crystallin is expressed predominantly in lens but, reminiscent of mammalian alphaB-crystallin, also has lower constitutive expression in heart, brain, skeletal muscle and liver. The chaperone-like activity of purified recombinant alphaB2 protein was assayed by measuring its ability to prevent the chemically induced aggregation of alpha-lactalbumin and lysozyme. At 25 degrees C and 30 degrees C, zebrafish alphaB2 showed greater chaperone-like activity than human alphaB-crystallin, and at 35 degrees C and 40 degrees C, the human protein provided greater protection against aggregation. 2D gel electrophoresis indicated that alphaB2-crystallin makes up approximately 0.16% of total zebrafish lens protein. Zebrafish is the first species known to express two different alphaB-crystallins. Differences in primary structure, expression and chaperone-like activity suggest that the two zebrafish alphaB-crystallins perform divergent physiological roles. After gene duplication, zebrafish alphaB2 maintained the widespread protective role also found in mammalian alphaB-crystallin, while zebrafish alphaB1 adopted a more restricted, nonchaperone role in the lens. Gene duplication may have allowed these functions to separate, providing a unique model for studying structure-function relationships and the regulation of tissue-specific expression patterns.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping