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Haifan Lin PhD

Professor of Cell Biology, of Genetics and of Obstetrics, Gynecology, and Reproductive Sciences; Director, Yale Stem Cell Center

Research Interests

Stem cell RNA-mediated epigenetic programming, post-transcriptional regulation


Research Summary

We study molecular mechanisms underlying the self-renewing division of stem cells. Currently, we focus on small RNA-mediated epigenetic programming and translational regulation that are required for the self-renewal of germline and embryonic stem cells. Meanwhile, we are exploring the clinical implications of our findings. Stem cells are characterized by their abilities to self-renew and to produce numerous differentiated daughter cells. These two special properties enable stem cells to play a central role in generating and maintaining most tissues in higher organisms. Over-proliferation of stem cells can cause cancer, whereas under-proliferation of stem cells leads to tissue dystrophy, anemia, immuno-deficiency, or infertility. Drosophila and the mouse represent two powerful systems for studying stem cells since they allow easy access to combined genetic, cell biological, and molecular analyses. We use Drosophila as a pilot model to explore molecular mechanisms underlying stem cell division, and the mouse as an advanced model to expand what we learn from Drosophila to mammalian and human systems. Previously, we identified germline stem cells in the Drosophila ovary and revealed their self-renewing asymmetric division. We and others showed that the asymmetric division of these stem cells is controlled by both niche signaling and intracellular mechanisms. Using systematic genetic screens, we have identified key genes involved in both niche signaling and intracellular regulation of stem cell division. Among them, piwi/argonaute genes represent the only known family of genes required for stem cell self-renewal in both animal and plant kingdoms. Currently, our research is focused on epigenetic programming and translational regulation of germline stem cell self-renewal mediated by the Piwi/Argonaute proteins and a novel class of non-coding small RNAs called piwi-Interacting RNAs (piRNAs) that we and others recently discovered. Meanwhile, we have begun to explore the role of these mechanisms in human embryonic stem cell division and oncogenesis.


Selected Publications

  • Ross, R., J., Weiner, M. M., and Lin, H. PIWI Proteins and piRNAs in the Soma. Nature (in press)
  • Juliano, C. E., Reich, A., Liu, N., Uman, S., Wessel, G., W., Steele, R. E., and Lin, H. (2013) Analysis of the PIWI-piRNA pathway in Hydra somatic stem cells. PNAS (in press).
  • Mani, S. R*, Megosh, H * and Lin, H. (2013) PIWI proteins are essential for early Drosophila embryogenesis. Developmental Biology (*co-first authors; in press)
  • Chang, E. and Lin, H. (2013) Repressing the repressor: a role of a lincRNA in embryonic stem cell self-renewal. Developmental Cell 25:1-2.
  • Saxe, J. P., Chen, M., Zhao, H., and Lin, H. (2013) Tdrkh is essential for spermatogenesis and participates in primary piRNA biogenesis in the germline. EMBO J. 32, 1869-1885.
  • Huang, X. A. *, Yin*, H., Sweeney, S., Raha, D., Snyder, M. and Lin, H. (2013) A major epigenetic programming mechanism guided by piRNAs. Developmental Cell 24 :502-516 (*co-first authors ; Featured Article)
  • Darricarrère, N., Liu, N., Watanabe, T., and Lin, H. (2013) The function of Piwi, a nuclear Piwi/Argonaute protein, is independent of its slicer activity, PNAS 110:1297-1302.
  • Nolde, M.J., Cheng E.-C., Guo, S., Lin, H. (2013) Piwi genes are dispensable for normal hematopoiesis in mice. PLoS ONE 8: e71950. doi:10.1371/ journal. pone.0071950.
  • Peng, J. and Lin, H. (2013) Beyond Transposons: the Epigenetic and Somatic Functions of the Piwi-piRNA Mechanism. Current Opinion in Cell Biology 25, 190–194.
  • Yin, H., Lin, H. (2013) Small RNA Discovery and Expression Analysis by High throughput Sequencing. In Genomic analysis using high-throughput sequencing (eds. Snyder, M. et al.) Cold Spring Harbor Laboratory Press. pp1-12.

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