Nancy E. Cooke, M.D.

faculty photo
Emeritus Professor of Medicine
Director, Transgenic and Chimeric Mouse Facility, School of Medicine, University of Pennsylvania
Department: Medicine

Contact information
547A Clinical Research Building
415 Curie Blvd.
Philadelphia, PA 19104-6145
Office: (215) 573-6638
Fax: (215) 573-2326
B.S. (Chemistry)
Wellesley College, Case Western Reserve University, 1970.
M.D. (Medicine)
Case Western Reserve University, 1974.
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Description of Research Expertise

Research Interests
The role of chromatin structure in long-range eukaryotic gene regulation.

Key words: chromatin structure, histone modifications, growth hormone gene, chorionic somatomammotropin gene, Pit-1, pituitary, placenta, transcriptional controls, mRNA expression.

Description of Research
Long-Range, Epigenetic Gene Activation by the Growth Hormone Locus Control Region.

The human growth hormone (hGH) gene cluster includes 5 genes: the pituitary hGH-N gene, and hCS-A, hCS-L, hGH-V, and hCS-B expressed in placenta. These 5 genes are regulated by a locus control region (LCR) located in the far 5’ region of this multigene locus. The B-cell specific CD79b/Igß gene is interposed between the hGH LCR and the hGH-N gene. The LCR is made up of 5 DNaseI hypersensitive sites (HS) located between -14.5 kb (HSI) and -32 kb (HSV) 5' to hGH-N. These HS are only present in placenta and/or pituitary. When this 32 kb domain plus the linked GH genes are present in a transgenic construct, transgenic mice reproducibly and robustly express the hGH-N gene specifically in pituitary somatotropes and the hCS genes specifically in the placenta. Expression in both tissues is copy-number-dependent and site-of-integration independent. This expression is paralleled by the establishment of a pituitary-specific 32 kb acetylated chromatin domain encompassing the hGH LCR and the contiguous hGH-N promoter. Levels of histone acetylation peak at the centrally located HSI,II. Determinants critical to hGH-N activation map to an array of three Pit-1 sites at HSI. Remarkably, deletion of HSI (99 bp) leads to a loss of histone acetylation throughout the 32 kb domain and >20-fold decrease in hGH-N expression. The acetylated domain encompassing the hGH LCR and hGH-N is organized into two pituitary-specific sub-domains defined by histone H3K4 tri-methylation (H3K4 tri-me); one sub-domain encompasses the LCR region including the CD79b/Igß locus while a second sub-domain encompasses hGH-N. Of note, the epigenetic modifications within the LCR lead to “bystander transcriptional activation” of the adjacent B-cell specific CD79b/Igß gene. These two sub-domains are separated by an intervening segment of minimally modified chromatin. By ChIP, RNA PolII is present throughout the hGH LCR as well as at the active hGH-N gene, and this pituitary-specific distribution of PolII is bimodal, closely paralleling the distribution of H3K4 tri-me. RT-PCR reveals non-coding, bi-directional RNA transcripts in this same region, confirming the presence of actively transcribing PolII within the hGH LCR. Deletion of HSI (99 bp) results in the marked and coordinate loss of the H3K4 tri-me, diminution of PolII recruitment within the LCR, and loss of the non-coding RNA transcripts. Insertion of a PolII terminator downstream of HSI,II blocks CD79b transcription and represses hGH-N expression, documenting a regulatory role for the noncoding transcripts and linking the “bystander” CD79b transcription to hGH-N regulation. Ongoing experiments will attempt to further understand the role of noncoding and CD79b transcripts in hGH-N gene regulation; to determine whether DNA looping between the LCR and GH genes is essential; to understand how the LCR activates the four placental GH genes.

The significance of these lines of investigation will be the detailed understanding of the regulation of the hGH/hCS gene cluster by its LCR via epigenetic changes in these tissues. These findings will serve as the foundation for a sophisticated understanding of the pathophysiology of human growth and development, and the role of epigenetic regulation of CD79b/Igß.

Description of Clinical Expertise

general adult endocrinology

Description of Other Expertise

genetically modified mouse models, mouse embryo cryopreservation

Selected Publications

Ho, Y., Tadevosyan, A., Liebhaber, S. A., Cooke, N. E.: The juxtaposition of a promoter with a locus control region transcriptional domain activates gene expression. EMBO Reports 9: 891-898, 2008.

Zella, LA, Kim, S, Shevde, NK, Hollis, B.W., Cooke, N.E., Pike, J.W.: Vitamin D-binding protein influences total circulating levels of 1,25-dihydroxyvitamin D3 but does not directly modulate the bioactive levels of the hormone in vivo. Endocrinology 149: 3656-3667, 2008.

Kimura, A. P., Sizova, D., Handwerger, S., Cooke, N. E., Liebhaber, S. A.: Epigenetic activation of the human growth hormone gene cluster during placental cytotrophoblast differentiation. Molecular Cellular Biology 27(18): 6555-68, 2007.

Hiroki, T., Liebhaber, S. A., Cooke, N. E.: An intronic locus control region plays an essential role in the establishment of an autonomous hepatic chromatin domain for the human vitamin D-binding protein gene. Molecular Cellular Biology 27(21): 7365-80, 2007.

Ho Y, Elefant F, Liebhaber SA, Cooke NE: Locus control region transcription plays an active role in long-range gene activation. Molecular Cell in press, 2006.

Yoo, E. J., Cajiao, I., Kim, J. S., Kimura, A. P., Zhang, A., Cooke, N. E., Liebhaber, S. A.: Tissue-specific chromatin modifications at a multigene locus generate asymmetric transcriptional interactions. Molecular Cellular Biology 26(15): 5569-79, 2006.

Cajiao, I., Zhang, A., Yoo, E. J., Cooke, N. E., Liebhaber, S. A.: Bystander gene activation by a locus control region. EMBO J 23(19): 3854-63, 2004.

Su, Y., Balice-Gordon, R. J., Hess, D. M., Landsman, D. S., Minarcik, J., Golden, J., Hurwitz, I., Liebhaber, S. A., Cooke, N. E.: Neurobeachin is essential for neuromuscular synaptic transmission. J Neuroscience 24(14): 3627-36, 2004.

Kimura AP, Liebhaber SA, Cooke NE: Epigenetic modifications at the human growth hormone locus predict distinct roles for histone acetylation and methylation in placental gene activation. Molecular Endocrinology 18: 1018-32, 2004 Notes: (Cover Art).

Ho Y, Elefant F., Cooke NE, Liebhaber SA: A defined locus control region determinant links chromatin domain acetylation with long-range gene activation. Molecular Cell 9: 291-302, 2002.

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Last updated: 06/22/2012
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