Xin Chen (Johns Hopkins Univ)
November 6, 2019 -
12:00 pm to 1:00 pm
Thomas Laboratory 003
Xin Chen joined the Department of Biology at Johns Hopkins in 2008 after doing her postdoctoral work at Stanford University School of Medicine. Her research centers on epigenetic regulation of Drosophila germ cell differentiation from a stem cell lineage.
Asymmetry from symmetry or symmetry from asymmetry?
Many types of stem cells undergo asymmetric cell divisions to give rise to daughter cells with distinct cell fates: one that retains stem cell identity and another that differentiates. During asymmetric cell division, the genomic information is preserved through DNA replication followed by equal partition to the two daughter cells. A long-standing question has been how the epigenetic information of a stem cell is transferred to the daughter cells. Using the Drosophila male germline stem cell lineage, we found that epigenetic information is inherited asymmetrically during asymmetric stem cell divisions. We have proposed a two-step model to explain asymmetric epigenetic inheritance. (1) Prior to mitosis, preexisting and newly synthesized histones are differentially distributed on the two sets of sister chromatids. (2) During mitosis, the set of sister chromatids containing preexisting histones is segregated to the stem cell, while the set of sister chromatids enriched with newly synthesized histones is segregated to the other daughter cell that differentiates. Our recent studies have shed light on both steps. Together, our work illuminates how epigenetically distinct sister chromatids could be established and recognized for asymmetric inheritance, in order to generate genetically identical but epigeneticallydistinct daughter cells. Recent findings of the generality of this phenomenon will also be discussed
Free and open to the university community and the public.
Paul Schedl/Girish Deshpande, Department of Molecular Biology