penna

Matthew Penna

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Matthew Penna

Medical Scientist Training Program (MD/PhD)

Email

matthew.penna@bcm.edu

Positions

Medical Scientist Training Program (MD/PhD): Baylor College of Medicine
Houston, TX US

GS4: Translational Biology and Molecular Medicine
Baylor College of Medicine

Mentor - Thomas Cooper, M.D.

Education

BS from University of Miami: 05/2016 - Coral Gables; Biomedical Engineering

PhD from Baylor College of Medicine: 12/2022 - Houston, Texas United States

Professional Statement

Postnatal muscle development is a highly dynamic period associated with extensive transcriptome remodeling. A significant aspect of this process is widespread changes in alternative splicing, required for adaptation of tissues to adult function. The functional significance of many developmental and tissue specific alternative splicing transitions is unknown. These splicing events have significant implications since reversion of adult mRNA isoforms to fetal isoforms is observed in many skeletal muscle diseases.

Limch1 is a putative actin-binding protein with LIM and calponin homology domains and several protein isoforms of unknown significance, generated by alternative splicing. The Limch1 gene expresses a ubiquitous protein isoform (uLimch1) in most tissues and a skeletal muscle specific isoform that predominates in adult skeletal muscle (mLimch1). mLimch1 contains an additional internal and in frame 454 amino acids encoded by six contiguous exons simultaneously included after birth. The developmental regulation and tissue specificity of this splicing transition is conserved in mouse and human. However, the significance of including these six exons of Limch1 in adult muscle is yet to be determined. To determine the physiologically relevant functions of mLimch1 and uLimch1 isoforms, CRISPR-Cas9 was used to delete the genomic segment containing the 6 alternatively spliced exons of Limch1 in vivo, thereby forcing the constitutive expression of the predominantly fetal isoform, uLimch1 in adult skeletal muscle (Limch1 6exKO). Grip strength analysis showed that adult male and female mice from two independent homozygous (HOM) Limch1 6exKO founder lines had significant muscle weakness compared to wild-type (WT) age-matched controls. By investigating the functional, spatial, and protein binding characteristics of mLimch1, the role of tissue specific regulation of Limch1 in skeletal muscle homeostasis will be uncovered. The results obtained from these studies will contribute to our understanding of the significance of RNA processing in skeletal muscle development and disease.