The germline is the only cell lineage capable of giving rise to the gametes. Defective germline development results in reduction or elimination of germ cells and ultimately causes infertility in humans, which affects 10- 15% of couples. Germ cell development begins early during embryonic development. After specification of primordial germ cells (PGCs), transcription is transiently repressed in PGCs. This is in stark contrast to the development of somatic lineages, which often relies on the activation of complex transcriptional programs. The establishment of such a transient genome-wide transcriptionally repressive state is critically important for early stages of the germline development, because it prevents PGCs from responding to surrounding signals that specify somatic cell fates. Failure to repress transcription during early stages of PGC development causes somatic differentiation and apoptosis of PGCs, which eventually leads to elimination of germ cells from the embryo. Understanding how this global transcriptionally repressive state is established in PGCs thus is highly relevant to human reproductive health. Our preliminary studies suggest that Dnd1, a RNA-binding protein required for vertebrate germ cell development, plays an essential role in establishing the genome- wide transcriptionally repressive state in PGCs. We found that Dnd1 protein is rapidly degraded by autophagy, making it intrinsically unstable. During development, Dnd1 is expressed at the right time and in the right place, and is required for the expression of Nanos1, which represses transcription in PGCs. We hypothesize that the genome-wide transcriptionally repressive state in PGCs is established through precisely regulated expression of Dnd1 protein.
Specific aims are:
Aim 1 : To determine if Dnd1 is a central upstream regulator of the transcriptional repression in PGCs.
Aim 2 : To investigate the mechanisms through which Dnd1 regulates nanos1 translation.
Aim 3 : To determine whether autophagy- dependent Dnd1 turnover is important for the germline development.
Since human infertility affects 10-15% of couples, a deeper understanding of the development of the germline, the only cell lineage capable of giving rise to the gametes, is highly relevant to human reproductive health. Proper germline development requires the establishment of a transient genome-wide transcriptionally repressive state in early primordial germ cells (PGCs) to prevent somatic differentiation and apoptosis of PGCs. Here we propose to study in detail how this genome-wide transcriptionally repressive state is established in PGCs. Such knowledge will provide advances relevant to stem cell, developmental, and reproductive biology.
|Vinyoles, M; Del Valle-Pérez, B; Curto, J et al. (2017) Activation of CK1? by PP2A/PR61? is required for the initiation of Wnt signaling. Oncogene 36:429-438|
|Chorghade, Sandip; Seimetz, Joseph; Emmons, Russell et al. (2017) Poly(A) tail length regulates PABPC1 expression to tune translation in the heart. Elife 6:|
|Aguero, Tristan; Jin, Zhigang; Chorghade, Sandip et al. (2017) Maternal Dead-end 1 promotes translation of nanos1 by binding the eIF3 complex. Development 144:3755-3765|
|Krishnamurthy, Vishnu V; Turgeon, Aurora J; Khamo, John S et al. (2017) Light-mediated Reversible Modulation of the Mitogen-activated Protein Kinase Pathway during Cell Differentiation and Xenopus Embryonic Development. J Vis Exp :|
|Jin, Zhigang; Liang, Feng; Yang, Jing et al. (2017) hnRNP I regulates neonatal immune adaptation and prevents colitis and colorectal cancer. PLoS Genet 13:e1006672|
|Jin, Zhigang; Schwend, Tyler; Fu, Jia et al. (2016) Members of the Rusc protein family interact with Sufu and inhibit vertebrate Hedgehog signaling. Development 143:3944-3955|
|Krishnamurthy, Vishnu V; Khamo, John S; Mei, Wenyan et al. (2016) Reversible optogenetic control of kinase activity during differentiation and embryonic development. Development 143:4085-4094|
|Yang, Jing; Aguero, Tristan; King, Mary Lou (2015) The Xenopus Maternal-to-Zygotic Transition from the Perspective of the Germline. Curr Top Dev Biol 113:271-303|