Sarah Elgin

Professor of Biology
Howard Hughes Medical Institute Professor
Viktor Hamburger Professor Emerita in Arts & Sciences
PhD, California Institute of Technology
research interests:
  • Chromatin Structure and Gene Expression in Drosophila
  • Chromosomal Proteins
  • Heterochromatin/Euchromatin
  • Dot Chromosome
  • RNAi in Heterochromatin Formation

contact info:

mailing address:

  • CB 1137
  • ST. LOUIS, MO 63130-4899
image of book cover

Professor Elgin is interested in the role that chromatin structure plays in gene regulation. Her laboratory works with Drosophila melanogaster, combining biochemical, genetic and cytological approaches.

The Elgin Lab is interested in the role that chromatin structure plays in gene regulation, both effects from packaging large domains and local effects of the nucleosome array. Working with Drosophila melanogaster, we have used a transposable Pelement containing a copy of the white gene, a visible marker for gene silencing, and a copy of hsp26, a well-characterized inducible gene, to examine the effect of insertion into different chromosomal domains. While these genes are fully active in euchromatic domains, silencing (similar to Position Effect Variegation) is observed on insertion into pericentric heterochromatin, telomeres, and sites within the small fourth chromosome. Both changes in the local nucleosome array, and the spatial organization of the nucleus, appear critical in determining gene silencing. The fourth chromosome, which appears entirely heterochromatic by many criteria, but has ~80 genes, is the focus of our studies. Mapping experiments indicate that heterochromatin formation can be targeted by the presence of a repetitious element, 1360, and perhaps by other similar elements. Genetic analysis has shown that heterochromatic silencing is dependent on the RNAi machinery.

Work is ongoing to determine the mechanism of heterochromatin targeting, and to analyze the role of critical heterochromatin-associated proteins, including HP1 and HP2. The silencing that occurs at tandem repeats is of particular interest, with investigations of a GAA310 repeat and a lacO256 repeat array under current investigation.

recent courses

Research Explorations in Genomics

A collaborative laboratory investigation of a problem in comparative genomics, utilizing a variety of bioinformatics tools to manage and investigate large data sets (currently including genomic sequences, gene predictions, sequence conservation, gene expression). In spring '18 the research problem involves improving the sequence of a region of the Drosophila eugracilis genome, and working with one of these sequences to examine patterns of genome organization, gene structure and gene regulation. Prerequisites: Bio 297A, Chemistry 111/112, 151/152. While Bio 3371 or Bio 437, and some familiarity with computers would be advantageous, this is NOT required. Permission of Dr. Sarah Elgin is required. Fulfills the upper-level laboratory requirement for the Biology major.

    Molecular Basis of Heredity

    Examines the structure of DNA, RNA, DNA repair, and genomics, and provides a rigorous study of what many scientists believe is the most central area of biology. Course builds on the themes of biochemistry and molecular biology introduced in Matter and Energy Transformations. A genomics section will provide an in depth look at some of the topics on molecular evolution that were first covered in Biological Evolution. Closed registration - for participants in the NSF Institute Masters in Biology program or by permission of the Associate Director of the Institute for School Partnership.

      Selected Publications

      Leung, W….[940 students, 72 faculty]…Elgin, SCR (2015)  The Drosophila Muller F elements maintain a distinct set of genomics properties over 40 million years of evolution.  G3: GENES, GENOMES, GENETICS 5: 719-740.

      Ho, JW, Jung YL, Liu T, Alver BH, Lee S, Ikegami K, Sohn KA, Minoda A, Tolstorukov MY, Appert A, Parker SC, Gu T, Kundaje A, Riddle NC, Bishop E, Egelhofer TA, Hu SS, Alekseyenko AA, Rechtsteiner A, ….[42 additional co-authors]…Kingston RE,  Kim JH, Bernstein BE, Dernburg AF,Pirrotta V, Kuroda MI, Noble WS, Tullius TD, Kellis M, MacAlpine DM, Strome S, Elgin SC, Liu XS, Lieb JD, Ahringer J, Karpen GH, Park PJ  (2014) Comparative analysis of metazoan chromatin organization. Nature512z; 449-52. PMID: 25164756

      Eissenberg, JC & SCR Elgin (2014) HP1a: A structural chromosomal protein regulatingtranscription.  Tr Genetics 30: 103-10.  PMCID: PMC3991861

      Gu, T, and Elgin, SCR (2013)  Maternal delpletion of Piwi, a component of the RNAi   system, impacts heterochromatin formation in Drosophila.  PLoS Genetics    9: e1003780/ PMCID: PMC3777992

      Riddle, NC, YL Jung, T Gu, AA Alekseyenko, D Asker, H Gui, PV Kharchenko, A Minoda, A Plachetka, YB Schwartz, MY Tolstorukov, MI Kuroda, V Pirrotta, GH Karpen, PJ Park, SCR Elgin. (2012) “Enrichment of HP1a on Drosophila chromosome 4 genes creates an alternative chromatin structure critical for regulation in this heterochromatic domain,”  PLoS Genetics 8: e1002954 PMCID: PMC3447959

      Wang, S H, and Elgin, SCR (2011) “Drosophila Piwi functions downstream of piRNA      production mediating a chromatin-based silencing mechanism in female germline,” Proc Natl Acad Sci USA. 108: 21164-69. PMCID: PMC3248523.