A proteome map of the zebrafish (Danio rerio) lens reveals similarities between zebrafish and mammalian crystallin expression.
OBJECTIVE
To characterize the crystallin content of the zebrafish lens using two-dimensional gel electrophoresis (2-DE). These data will facilitate future investigations of vertebrate lens development, function, and disease.


METHODS
Adult zebrafish lens proteins were separated by 2-DE, and the resulting spots were identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). The relative proportion of each crystallin was quantified by image analysis, and phosphospecific staining was used to identify phosphorylated alpha-crystallins. The proportion of each crystallin in the soluble and insoluble fraction of the lens was also determined by resolving these lens fractions separately by 2-DE.


RESULTS
alpha-, beta-, and gamma-crystallins comprised 7.8, 36.0, and 47.2% of the zebrafish lens, respectively. While the alpha-crystallin content of the zebrafish lens is less than the amounts found in the human lens, the ratio of alphaA:alphaB crystallin is very similar. The phosphorylation pattern of zebrafish alphaA-crystallins was also similar to that of humans. The most abundant gamma-crystallins were the diverse gammaMs, comprising 30.5% of the lens. Intact zebrafish crystallins were generally more common in the soluble fraction with truncated versions more common in the insoluble fraction.


CONCLUSIONS
While the total alpha- and gamma-crystallin content of the zebrafish lens differs from that of humans, similarities in alpha-crystallin ratios and modifications and a link between crystallin truncation and insolubility suggest that the zebrafish is a suitable model for the vertebrate lens. The proteome map provided here will be of value to future studies of lens development, function, and disease.
Posner
Mason
M
Department of Biology, Ashland University, Ashland, OH; 2Department of Chemistry, Ashland University, Ashland, OH 44805, USA. mposner@ashland.edu
Hawke
Molly
M
Lacava
Carrie
C
Prince
Courtney J
CJ
Bellanco
Nicholas R
NR
Corbin
Rebecca W
RW
D000818:Animals; D003459:Crystallins / Q000378:metabolism*; D003720:Densitometry; D015180:Electrophoresis, Gel, Two-Dimensional; D005786:Gene Expression Regulation; D006801:Humans; D007908:Lens, Crystalline / Q000737:chemistry*; D050505:Mutant Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D020543:Proteome / Q000032:analysis*; D017386:Sequence Homology, Amino Acid; D012995:Solubility; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D015027:Zebrafish / Q000378:metabolism*; D038201:alpha-Crystallins / Q000737:chemistry / Q000378:metabolism; D038204:beta-Crystallins / Q000737:chemistry / Q000378:metabolism; D038222:gamma-Crystallins / Q000737:chemistry / Q000378:metabolism
D003459:Crystallins; D050505:Mutant Proteins; D010750:Phosphoproteins; D020543:Proteome; D038201:alpha-Crystallins; D038204:beta-Crystallins; D038222:gamma-Crystallins