Using zebrafish to study the expression of genes involved in human disease

Amy Drossman

The beginning of the Fall semester has slowed our news updates.  And while our summer research program has ended, students are back in lab continuing with projects started over the summer months.  Biology major Amy Drossman is continuing with her honors thesis project on the expression of the vertebrate stress protein alpha B-crystallin.

Alpha Bb-crystallin is a protein that is found throughout many different tissues within the body and is known to be involved in fiber cell differentiation in the lens. It also plays a protective role in demyelinating diseases such as Multiple Sclerosis and when malfunctioning is known to be involved in several different cancers. It is important to understand what is regulating the expression of alpha Bb-crystallin in order to find treatments and cures for the diseases it is known to be involved in.  Alpha Bb-crystallin is located in a head-to-head manner with another gene within the zebrafish genome and my focus is on the 6,000 base pair (6kb) promoter region between these two genes that is known to regulate expression and function in both. In order to determine what portions of the 6kb region are involved in regulating when and where alpha Bb-crystallin is expressed, serial truncations are carried out in order to amplify only a certain region of the entire promoter. These portions (1kb, 2kb, 3kb, 4kb, and 5kb) can then be attached to a green fluorescent protein (GFP) reporter gene and injected into zebrafish embryos. When visualized under a fluorescent microscope, the fish will glow green in regions where the portion of the promoter is regulating gene expression. A similar promoter region for alpha B-crystallin is found in mammals, making zebrafish a model organism for this study. Since the zebrafish embryo is transparent, changes in expression can be easily visualized in the living embryo whereas in a mammalian organism, the embryo has to be sacrificed in order to visualize expression since the embryo is not transparent.

- Amy Drossman