DNA-binding Proteins in Lumbriculus Sperm

Name of Award

3M Student-Faculty Collaborative Grants - Small Scale

Date Awarded

Summer 6-2-2016



Project Description

Kay Tweeten, PhD, Professor of Biology, was awarded $1000 for a 3M Student-Faculty Collaborative Small Scale grant for her study examining DNA-binding Proteins in Lumbriculus Sperm. The proposed project would analyze Lumbriculus sperm for protamine-like molecules, gaining insights into the composition and biochemical properties of DNA-binding proteins from these invertebrates. The Tweeten laboratory has determined that during the summer months, Lumbriculus in natural habitats in Minnesota is extensively sexually reproducing. This provides us with access to large numbers of sexually mature Lumbriculus specimens and has allowed us to conduct experiments on the morphology, number and organization of reproductive structures in these annelids. During formation of sperm in vertebrates such as humans, the DNA is extensively compacted for packaging within the sperm head, with histone proteins typically being replaced by protamines. The protamines are low molecular weight, highly basic proteins that tightly condense the DNA, reducing nuclear size and providing for small, motile cells. The biochemical properties and functional roles of protamines in sperm has been explored only to a limited extent in invertebrates. Protamine-like molecules have been found in sperm from mollusks and the fruit fly, Drosophila. While these proteins are similar to mammalian protamines in their high levels of arginine and cysteine, their overall amino acid composition is distinct and they are higher in molecular weight. Acid extraction techniques followed by urea gel electrophoresis will be used to determine if protamines are present in Lumbriculus sperm. Further analysis of the extracted proteins will allow comparison of their biochemical properties to those of protamines from other invertebrates and vertebrates.


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