Cytokine gene expression is one of the most important functions of helper T-cells and one of the most precisely regulated. While much is known about the mechanisms controlling cytokine gene expression in response to stimulation, the developmental aspects of this function have remained more obscure. The well-characterized enhancer of the IL-2 gene, for example, has been notoriously inefficient in regulating reporter gene expression in transgenic mice, suggesting that the regulatory sequences needed for correct initial opening of the chromatin in a developmental context might be separate from the known enhancer. Another mystery is the mechanism of the surprising """"""""monoallelic"""""""" expression that is seen in many IL-2 producing cells: does this reflect an epigenetically inherited chromatin difference between alleles, a natural version of position effect variegation? Or does this simply reflect the steeply cooperative nature of transcription factor binding to the IL-2 promoter in any given case of stimulation? The investigator has developed unique tools to address this problem in the last project period of this application. Using DNase hypersensitive site mapping, she has located a new series of candidate regulatory sequences upstream of all regions previously characterized. This analysis has guided her in generating two new transgenic constructs in which the IL-2 regulatory region drives expression of Enhanced Green Fluorescent Protein (GFP). The larger of these constructs gives cell-type-specific, activation-sensitive, approximately copy number-dependent expression in 4/4 well-studied transgenic lines and in 10/11 transgenic line overall. The fidelity of expression even at high copy number gives unparalleled sensitivity for detection of living cells that have activated IL-2 transcription factors. In the next project period, the investigator wishes to exploit the exciting opportunities that these mice give us to answer three questions: (10 what sequences are responsible for the earliest onset of IL-2 expression in primitive lymphoid precursors; (2) what new cis-elements in the IL-2 flanking sequence confer position-independent expression in a full range of appropriate cell types: and (3) whether early expression of a particular IL-2 regulatory sequence locus is associated with establishing a later preference for activation of that locus in responses to stimulation.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
5R01AG013108-19
Application #
6631499
Study Section
Immunobiology Study Section (IMB)
Program Officer
Fuldner, Rebecca A
Project Start
1982-06-01
Project End
2005-02-28
Budget Start
2003-03-15
Budget End
2004-02-29
Support Year
19
Fiscal Year
2003
Total Cost
$348,618
Indirect Cost
Name
California Institute of Technology
Department
Type
Schools of Arts and Sciences
DUNS #
009584210
City
Pasadena
State
CA
Country
United States
Zip Code
91125
Rothenberg, Ellen V (2016) Eric Davidson: Steps to a gene regulatory network for development. Dev Biol 412:S7-19
Rothenberg, Ellen V (2015) Immune Cell Identity: Perspective from a Palimpsest. Perspect Biol Med 58:205-28
Adachi, Satoko; Rothenberg, Ellen V (2005) Cell-type-specific epigenetic marking of the IL2 gene at a distal cis-regulatory region in competent, nontranscribing T-cells. Nucleic Acids Res 33:3200-10
Yui, Mary A; Rothenberg, Ellen V (2004) Deranged early T cell development in immunodeficient strains of nonobese diabetic mice. J Immunol 173:5381-91
Yui, Mary A; Sharp, Leslie L; Havran, Wendy L et al. (2004) Preferential activation of an IL-2 regulatory sequence transgene in TCR gamma delta and NKT cells: subset-specific differences in IL-2 regulation. J Immunol 172:4691-9
Rothenberg, Ellen V; Dionne, Christopher J (2002) Lineage plasticity and commitment in T-cell development. Immunol Rev 187:96-115
Yui, M A; Hernandez-Hoyos, G; Rothenberg, E V (2001) A new regulatory region of the IL-2 locus that confers position-independent transgene expression. J Immunol 166:1730-9
Anderson, M K; Hernandez-Hoyos, G; Diamond, R A et al. (1999) Precise developmental regulation of Ets family transcription factors during specification and commitment to the T cell lineage. Development 126:3131-48
Rothenberg, E V; Telfer, J C; Anderson, M K (1999) Transcriptional regulation of lymphocyte lineage commitment. Bioessays 21:726-42
Wang, H; Diamond, R A; Yang-Snyder, J A et al. (1998) Precocious expression of T cell functional response genes in vivo in primitive thymocytes before T lineage commitment. Int Immunol 10:1623-35

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