Mentor: Andor Kiss, Ph.D.

The global population is aging, and as a consequence, the number of individuals experiencing age-related symptoms is increasing. Senile cataracts occur when the eye lens becomes cloudy due to the buildup of unfolded, or denatured, proteins over time. Cataracts are the leading cause of blindness worldwide and cause a significant decline in quality of life. They are particularly difficult for individuals who live in societies that have minimal accommodations for the sight-impaired. To better understand the formation and structure of cataracts, and the lack thereof in animals that are resistant to cataract formation, we isolated and sequenced the lens crystallin cDNAs from the red caiman. Lens crystallins are the proteins in the eye lens that impart the transparent optical nature to this tissue, and when these crystallins are disrupted, the result is cataract formation. Caimans, being crocodilian, are an evolutionarily ancient and very successful group of animals, meaning that their genome is well-adapted to life on earth. Being cold-blooded, aquatic, and native to the tropics, caimans are subject to a lot of environmental stress. This makes them an ideal candidate to study regarding life-long lens crystallin structure and stability. Lens crystallins, like many proteins, come in a variety of subtle variations – called isoforms. These isoforms arise due to small changes in the genetic code that cause changes in key amino acids during alternative splicing. These variants all have similar, but slightly different structures when folded into their final forms as proteins. We used a novel technology that uses full-length isoform sequencing (Iso-Seq), a method of long-read cDNA sequencing, to inventory the mRNA transcript-level variations in the caiman lens crystallins that result in their many isoforms. With this data, we hope to pinpoint not only the isoforms that may be particularly stable or resistant to stress, but also any mutations at specific amino acid residues that make them uniquely resistant to senile insult. Current treatment for cataracts is surgical, but with the increasing aging population, cataract surgery may prove to be ineffective at meeting the demand for cataract treatment. Therefore, the hope is for this data to be used in the development of a non-surgical treatment for cataracts, such as a prophylactic treatment similar to fluorination of drinking water, or the addition of folic acid to cereal grains.

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