PROJECT SUMMARY/ABSTRACT Congenital malformations arising from errors during fetal development are the leading cause of infant death in the United States. Physiologic development relies on an orchestration of gene regulatory mechanisms. These mechanisms instruct pluripotent cells in the embryo to specify into hundreds of differentiated identities in the right place at the right time. Thus, to develop therapeutic strategies against developmental diseases, there is a critical need to understand the gene regulation instructing cell fate. Both transcriptional and posttranscriptional regulation are known to instruct DNA and RNA processing of genes important in cell fate specification. Yet, a growing area of study has revealed that these regulatory mechanisms can interact to allow feedback, competition, or cooperativity between chromatin and RNA functions. However, a significant gap in knowledge is how this interplay contributes to human cell fate control. Preliminary data indicate that ILF2-ILF3, a heterodimeric, dual DNA- and RNA- binding protein, is critical for specifying human embryonic cell fates by regulating splicing of key chromatin regulators. This proposal aims to define the interplay between DNA and RNA regulation as a novel mechanism of human cell fate control. The following aims are designed to test the hypothesis that ILF2-ILF3 is a critical determinant of human cell identities through regulation of both chromatin and RNA. Aim 1 will suppress ILF2-ILF3 expression in two systems of differentiation of human pluripotent stem cells to test the hypothesis that ILF2-ILF3 is required for early cell fate transitions. Aim 2 will identify direct chromatin, RNA, and protein binding partners of ILF2-ILF3, and investigate downstream effectors, to test the hypothesis that ILF2-ILF3 regulates both transcriptional and post-transcriptional processes to specify cell fate. The long-term obiectives of this project are to determine a new mechanism driving human development at the molecular and cellular levels and advance strategies to prevent congenital diseases. This fellowship application is sponsored by Bruno Di Stefano, Ph.D., an expert stem cell biologist, and Jason Mills, M.D., Ph.D., a physician-scientist and expert in gastrointestinal cell plasticity, who will provide close guidance throughout the fellowship period. The training plan includes strategies to 1) Learn from accomplished scientists and physician-scientists that will advise the applicant through her training goals; 2) Undergo rigorous scientific training in stem cells and gene regulation; 3) Experience opportunities to improve scientific communication skills and expand professional networks; 4) Advance the applicant's clinical training, especially in pediatrics. The clinical and scientific training environment at Baylor College of Medicine is within the Texas Medical Center, the largest medical research complex in the world. This environment is ideal to foster the applicant's scientific an...