03/30/2026
By Kwok Fan Chow

The Kennedy College of Science, Department of Chemistry, invites you to attend a Ph.D. Dissertation defense by Prabath Swarna Sri Meemaduma entitled “Molecular Landscape of Rodent Masticatory Muscles: A Multi-omics Investigation of the Presence and Impact of Specialized Masticatory Isoforms.”

Date: Thursday, April 9, 2026
Time: 11 a.m.
Location: Olney Hall, Room 518

Committee:

  • Advisor: Matthew Gage, Ph.D., Department of Chemistry, University of Massachusetts Lowell
  • Jeffrey R. Moore, Ph.D., Department of Biological Science, University of Massachusetts Lowell
  • Frédéric Chain, Ph.D., Department of Biological Science, University of Massachusetts Lowell
  • Pengyuan Liu, Ph.D., Department of Chemistry, University of Massachusetts Lowell

Abstract:
Adaptations related to jaw muscles are subject to intense evolutionary pressure, since they directly influence the feeding efficiency and niche specialization of an organism. The presence of unique jaw muscle specific contractile proteins has been reported in several vertebrate classes associated with high bite forces. The first such jaw specific protein identified was masticatory myosin, which when expressed leads to unusually high contractile forces, higher calcium sensitivity, and moderate velocities compared to non-masticatory skeletal muscles. While multiple molecular studies have reported that jaw muscle expression of masticatory myosin is often accompanied by several other unique contractile forms of the myosin light chains and tropomyosin, the overall transcriptional variance and regulatory mechanisms between masticatory and non-masticatory muscles have not been widely explored.

This dissertation explores the transcriptomic landscape of masticatory isoform expression in gray squirrel jaw closer muscles (Superficial Masseter) in comparison to two other functionally and developmentally distinct muscles: the Anterior Digastric (Jaw opener), and Sternohyoid. Through a comparative transcriptomic analysis of these tissues in the gray squirrel (Sciurus carolinensis) and the non-masticatory isoform expressing rat (Rattus norvegicus); this study provides the first transcript-level confirmation of previously reported masticatory specific isoforms are encoded by MYL4 (embryonic/atrial myosin essential light chain), MYL5 (masticatory specific myosin regulatory light chain isoform) and TPM4 (tropomyosin). Additionally, IGSF22 was identified in the gray squirrel as a specialized masticatory isoform of myosin binding protein-C (MYBPC). Furthermore, this research reveals that a subunit of a known ‘ATP-dependent-chromatin-remodeling-complex’ subunit (SWI/SNF related chromatin remodeling complex) known as SMARCD3 is highly co-expressed with all identified masticatory isoforms, identifying it as a key transcriptional regulator governing the jaw muscle gene expression.

All interested students and faculty members are invited to attend.