Molecular Biology and Reproduction

Germline Stem Cell Biology

Stem cells located within many adult tissues are necessary to ensure lifelong tissue longevity. Stem cells accomplish this by balancing maintenance of the stem cell reservoir, in a process known as self-renewal, with the continuous production of daughter cells through the process of differentiation. In reproductive biology, the continuous production of sperm by males originates from a population of germline stem cells. Studies by our group and others demonstrate that disruptions in the formation of germline stem cells have lasting impacts on sperm production, fertility, and inheritance long into adulthood. Therefore, our group aims to better understand the mechanisms by which germline stem cells form and gain the capacity to support lifelong sperm production. Our recent studies demonstrate that the RUNX family of transcriptions factors are necessary for newly formed germline stem cells to both self-renew and differentiate to produce sperm. How RUNX proteins accomplish this dual regulation of two opposing processes remains unknown and an ongoing area of our research.

Paternal Epigenetic Inheritance

Sperm are classically categorized as specialized motile cells that deliver the paternal genome to complete fertilization. Contrary to this traditional viewpoint, however, discoveries of the last decade have demonstrated that sperm influences early embryo development and can ultimately shape the health, fitness, and survival of progeny. During sperm production, the paternal genome is tightly compacted into the sperm head via specialized chromatin proteins known as protamines. Most histones that control genomic structure and gene expression are replaced by protamines but a small subset are retained. The reason histones are retained within sperm isn’t fully understood but is linked to embryo health and fertility. Therefore, another ongoing focus of our group is to explore sperm histone retention across species and functionally understand why histones are retained within sperm.