EAGER: Reprogramming to the Totipotent State
Intellectual Merit. The totipotent state exists during a brief period of embryonic development soon after fertilization before implantation. In contrast to pluripotent embryonic stem cells (ESCs) or reprogrammed iPSCs, which have the potential to generate all embryonic tissue types, totipotent cells can produce both embryonic and extraembryonic tissues. To date, the totipotent state can be achieved by natural fertilization, or artificially by somatic cell nuclear transfer (aka cloning) or removal of epigenetic regulators in iPSCs. However, the efficiency of these approaches is relatively low, and require unknown factors in the oocyte cytoplasm to reprogram the somatic nucleus, or overexpression of multiple factors to reprogram somatic cells to iPSCs followed by removal of epigenetic regulators.
We have identified a simple strategy to completely reprogram iPSCs or adult somatic cells into totipotent-like cells. By reducing the activity of a single chromatin remodeling protein, we can increase a rare population of totipotent-like cells in iPSC cultures from 0.5% to 100%. Results from the mouse chimera assay indicate that our cells can generate both embryonic and extraembryonic tissues. Moreover, these cells have the capacity to self-renew akin to ESCs and iPSCs, a feature not present in 2C-like cells. Our cells therefore have characteristics of both the pluripotent and totipotent states. We have in vitro evidence that similar manipulations can reprogram somatic cells into totipotent-like cells. In this proposal, we use the in vivo mouse chimera assay to rigorously test whether these reprogrammed somatic cells are bona fide totipotent-like cells with the capacity to generate both embryonic and extraembryonic tissues, or the conceptus.
Broader Impacts. This proposal will use an early intervention & engagement strategy to help improve the declining retention rates among undergraduates at UTSA. I have established undergraduate courses in Contemporary Biology for freshmen and sophomores, and Cell Biology for mostly juniors. This gives me the unique opportunity to access 1st, 2nd, and 3rd year undergraduates. As part of their grade, students will be assigned to write a report about the current research and training experiences by one of our faculty members. This exercise will encourage students to better understand and become an integral part of the excitement and growth contributing to UTSAÃ¢â‚¬â„¢s mission to achieve tier-one research status. This strategy will help align the poor retention rates with the growth and investment in basic research at UTSA, and recruit potential students to participate in the research part of this proposal.