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Faculty Profile

Julie Secombe, Ph.D.

Dr. Julie Secombe

Associate Professor, Department of Genetics

 

Professional Interests

My lab has a long-term interest in understanding the function of the KDM5 family of transcriptional regulators.  KDM5 proteins have a unique combination of chromatin modifying and recognition domains that are likely to regulate gene expression through distinct mechanisms.  In addition, an ever-growing body of evidence links their dysregulation to human pathologies.  Of the four human KDM5 paralogs (KDM5A-D), three are clinically significant. KDM5A or KDM5B are overexpressed in a large number of cancers, and loss of function mutations in KDM5C are found in patients with X-linked intellectual disability. 

To-date, however, no effective therapies exist to treat disorders caused by KDM5 protein dysfunction, primarily because we do not have a comprehensive knowledge of KDM5 target genes, nor of the mechanisms by which KDM5 proteins regulate gene expression.  To dissect KDM5 function we use Drosophila since it encodes a single, essential, KDM5 ortholog thereby overcoming the complication of functional redundancy among the four mammalian paralogs.

We currently have a number of projects going on in the lab:

  • Determining how KDM5 acts with the oncoprotein Myc to regulate cell growth, as this is likely to be directly relevant to understanding how KDM5A/B causes cancer in humans.
  • Defining KDM5 target genes in larvae and in adults and defining the different mechanisms used by KDM5 to activate and repress gene expression.
  • Examining neuronal phenotypes of kdm5 mutant flies to gain insight into how loss of human KDM5C results in intellectual disability.
  • Generating and characterizing mutant fly strains harboring mutations that are analogous to those found in intellectual disability patients. Significantly, all missense mutations in KDM5C found in affected patients occur in evolutionarily conserved residues.

 

 

Selected Publications

Secombe, J., Pierce, S.B and R.N. Eisenman. (2004) Myc: A weapon of Mass destruction. Cell, 117:153-156

Brumby, A*., J Secombe*,J. Horsfield, M. Coombe, N. Amin, D. Coates, R. Saint and H. Richardson (2004) A genetic screen for dominant suppressors of a cyclin E hypomorphic mutation identifies novel regulators of S phase entry. Genetics 168:227-251 *Co-first authors.

Loo, L*., J. Secombe*, J.T. Little, L. Carlos, C. Yost, P-F Cheng, E.M. Flynn, B.A. Edgar and R.N. Eisenman. (2005) The transcriptional repressor dMnt is a regulator of growth and lifespan in Drosophila. Mol Cell Biol. 25:7078-91 *Co-first authors.

Secombe, J. and R.N. Eisenman (2007) The function and regulation of the JARID1 family of histone H3 lysine 4 demethylases: the Myc connection. Cell Cycle 6:1324-8

Secombe, J., L. Li, L. Carlos and R.N. Eisenman (2007) The Trithorax protein Lid is a trimethyl H3-K4 demethylase required for dMyc-induced growth. Genes Dev. 21:537-551

Grzeschik N.A., N. Amin, J. Secombe, A.M. Brumby and H. E. Richardson (2007) Abnormalities in cell proliferation and apico-basal cell polarity are separable in Drosophila lgl mutant clones in the developing eye. Dev. Biol. 311:106-23

Li, L., C. Greer, R.N. Eisenman and J. Secombe (2010) Essential functions of the histone demethylase Lid. PLoS Genetics 6(11):e1001221.

DiTacchio, L., Le, HD., Vollmers, C., Hatori, M., Witcher, M., Secombe, J. and Panda, P. (2011) Histone lysine demethylase JARID1a activates transcription regulators CLOCK-BMAL1 and influences the circadian clock. Science, 333:1881-1884.

Greer, C., Lee, M., Westerhof, M., Milholland, B., Spokony, R., Vijg, J. and Secombe, J (2013) Myc-dependent genome instability and lifespan in Drosophila. PLoS ONE, 8(9): e74641.

Li, L., Anderson, S., Secombe, J and R.N. Eisenman (2013) The Drosophila ubiquitin-specific protease Puffyeye regulates dMyc-mediated growth. Development, 140:1-12.

Liu, X., Greer, C., and J. Secombe (2014) KDM5 interacts with Foxo to modulate cellular levels of oxidative stress. PLos Genetics 10(10): e1004676

 

Material in this section is provided by individual faculty members who are solely responsible for its accuracy and content.

Contact

Albert Einstein College of Medicine
Jack and Pearl Resnick Campus
1300 Morris Park Avenue
Ullmann Building, Room 809
Bronx, NY 10461

Tel: 718.430.2698
Fax: 718.430.8778
julie.secombe@einstein.yu.edu

 
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