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Access Type

Open Access

Document Type


Degree Program

Animal Science

Degree Type

Master of Science (M.S.)

Year Degree Awarded


Month Degree Awarded



Testis, Kinase, Sperm, Phylogenetic, Epigenetic, Biochemical


The Testis Specific Serine Kinases (Tssks) are a family of proteins that show testis and sperm-specific expression. Members of this family are most conserved among mammals, however there are homologs in vertebrates like birds and amphibians, chordates, and other invertebrates like insects and cnidarians. This specific expression suggests that these kinases are highly regulated. Analysis of murine and human Tssk1, Tssk2, and Tssk6 sequences show that these genes are comprised of one exon each, suggesting they are retrotransposons. The expression of these genes shows their importance, since many retrotransposons are silenced due to the foreign nature of the DNA, and knock-out mouse models have shown that these kinases are required for fertility. Understanding the properties of these kinases not only expands our scientific knowledge, but also lends itself to understanding fertility issues in men as well as being a contraceptive target. We looked at an epigenetic regulation factor, DNA methylation at CpG dinucleotides, to see if this caused the testis-specific gene expression we saw. Tssk2 and preliminary results from Tssk1 showed that there is no differential methylation at CpG dinucleotides or between tissues. Preliminary results for Tssk6 did show one site that may be differentially methylated, thus the tissue specific expression. We then started looking further into biochemically characterizing TSSK1 and TSSK2 to determine functionally relevant sites and new substrates. Understanding how these kinases function in sperm is relevant in our understanding in the fertility field and poses new targets for developing contraceptives.


First Advisor

Pablo E Visconti

Second Advisor

Ana Maria Salicioni