Environmental Factor, December 2010, National Institute of Environmental Health Sciences
Upcoming distinguished lecture by Haifan Lin
By Angelika Zaremba
NIEHS will welcome stem cell researcher Haifan Lin, Ph.D., Dec. 14 as the latest speaker in the 2010-2011 Distinguished Lecture Series. Lin will present his research findings in a lecture titled "A Novel Small RNA-Mediated Epigenetic Mechanism Related to Stem Cells," hosted by NIEHS Principal Investigator Guang Hu, Ph.D. (http://www.niehs.nih.gov/research/atniehs/labs/escbl/pi/stemcell/index.cfm), head of the Stem Cell Biology Group in the Laboratory of Molecular Carcinogenesis.
Lin (http://medicine.yale.edu/genetics/people/haifan_lin.profile) is a professor of Cell Biology and Genetics at the Yale University School of Medicine, where he studies the mechanism of stem cell self-renewal in fruit flies, mice, and human cancer cells, and he is the founding director of the Yale Stem Cell Center. He co-founded and co-directed the Duke Stem Cell Research Program and is also a founding officer of the International Society for Stem Cell Research.
Lin's research team studies molecular mechanisms underlying the self-renewing division of stem cells. His group is focusing on epigenetic programming and post-transcriptional regulation mediated by Piwi/Argonaute proteins and a novel class of non-coding small RNAs called Piwi-interacting RNAs (piRNAs). The piRNA complexes are involved in transcriptional gene silencing via epigenetic regulation and represent a distinct small RNA pathway that is widely thought to function only in germline.
Lin's group is interested in the role of these molecular mechanisms in germline and embryonic stem cell division and oncogenesis. Over-proliferation of stem cells can cause cancer, whereas under-proliferation of stem cells leads to tissue dystrophy, anemia, immunodeficiency, or infertility.
Lin's team discovered the Piwi protein family and was one of the first to discover piRNAs. Soon afterwards the group identified a link between the Piwi-piRNA pathway and epigenetic regulation. Based on their results, Lin's team proposed a Piwi-piRNA guidance hypothesis, in which the Piwi-piRNA complex serves as a sequence-recognition machinery that recruits epigenetic effectors such as Heterochromatin Protein 1a (HP1a) to execute epigenetic regulation.
(Angelika Zaremba, Ph.D., is a visiting postdoctoral fellow in the NIEHS Laboratory of Signal Transduction Inositol Signaling Group.)