Data for: Impact of alpha crystallin loss on zebrafish lens development

<p class="MsoNormal">The <span>α</span>-crystallin small heat shock proteins contribute to the transparency and refractive properties of the vertebrate eye lens and prevent the protein aggregation that would otherwise produce lens cataracts, the leading cause of human blindness. There are conflicting data in the literature as to what role the <span>α</span>-crystallins may play in early lens development. In this study, we used CRISPR gene editing to produce zebrafish lines with mutations in each of the three <span>a</span>-crystallin genes (<em>cryaa</em>, <em>cryaba</em> and <em>cryabb</em>) to prevent protein production. The absence of each <span>α</span>-crystallin protein was analyzed by mass spectrometry, and lens phenotypes were assessed with differential interference contrast microscopy and histology. Loss of <span>α</span>A-crystallin produced a variety of lens defects with varying severity in larval lenses at 3 and 4 dpf but little substantial change in normal fiber cell denucleation. Loss of <span>α</span>Ba-crystallin produced no substantial lens defects. Our <em>cryabb</em> mutant produced a truncated <span>a</span>Bb-crystallin protein and showed no substantial change in lens development. Mutation of each <span>α</span>-crystallin gene did not alter the mRNA levels of the remaining two, suggesting a lack of genetic compensation. These data suggest that <span>α</span>A-crystallin plays some role in lens development, but the range of phenotype severity in null mutants indicates its loss simply increases the chance for defects and that the protein is not essential. Our finding that <em>cryaba</em> and <em>cryabb</em> mutants lack noticeable lens defects is congruent with insubstantial transcript levels for these genes in lens epithelial and fiber cells through five days of development. Future experiments can explore the molecular mechanisms leading to lens defects in <em>cryaa</em> null mutants and the impact of <span>α</span>A-crystallin loss during zebrafish lens aging.</p>