RIG: Analysis of ING proteins during avian follicular development

Reproduction requires continuous growth and ovulation of eggs from the ovary. Eggs grow in structures called follicles. In birds, the careful parceling of follicles into the active pool throughout the animal's reproductive life ensures a steady supply of oocytes for egg-laying. The mechanisms or pathways involved in this careful balance between activation and continued quiescence are unknown. However, dramatic changes in gene activity occur in follicular cells and this is associated with follicular activation and growth. These changes are part of a process called differentiation. The end result of follicular differentiation is the production of a fertile egg and important systemic hormones such as estrogen and progesterone. The long-term objective of the proposed research is to understand the intra-ovarian pathways involved in follicle activation and growth. The inhibitors of growth (ING) proteins are a newly discovered class of nuclear proteins that 'read' the state of the nuclear DNA (chromatin). ING proteins recruit modifying enzymes that repress chromatin and therefore inhibit differentiation. ING2 mRNA is high in quiescent avian follicles and decrease as follicles grow larger. The proposed research will test the hypothesis that ING2 inhibits follicular development by maintaining the nuclear DNA of follicular cells in a repressed state. Experiments will be conducted to test this hypothesis using a newly developed small follicle culture system in conjunction with molecular inhibition of ING2 mRNA (RNAi). These studies will yield valuable insight into a basic biological mechanism of cellular differentiation and ovarian development in birds. The PI is committed to the training and career advancement of qualified graduate and undergraduate students and in particular seeks to increase the pool of trainees from underrepresented groups in biology.