Differential expression of genes in a particular tissue, such as retina, is achieved by combinatoriaI action of transcription factors. Nrl is an evolutionarily-conserved bZIP transcription factor, identified in our laboratory by subtraction cloning. In the adult, high levels of Nrl transcripts are detected only in the retina. The Nrl protein shows strong homology to the product of a transforming oncogene, v-maf. The proteins of the Maf-Nrl subfamily recognize a long AP-1 like DNA sequence element, are shown to heterodimerize with selected bZIP proteins in vitro, and implicated in tissue-specific gene regulation. Several lines of evidence suggest that Nrl is involved in rhodopsin gene regulation. The underlying hypothesis is that in the adult retina Nrl plays a major role in regulating the expression of gene products that are needed for the appropriate fiinctioning of photoreceptors and other neurons. Since protein-protein interactions are a major determinant of transcriptional activity and can generate tremendous flexibility in target site selection, the objective of this proposal is to identify the proteins that specifically interact with Nrl and to elucidate the biological relevance of these interactions. To accomplish this, Specific Aim 1 proposes to evaluate whether any of the known bZIP proteins of the Fos, Jun, Maf-Nrl and NF-E2 p45 subfamilies is expressed in the adult retina and interacts with Nrl to modulate gene expression.
Specific Aim 2 focuses on the purification and characterization of retinal proteins that bind to the Nrl-response element in the rhodopsin promoter.
Specific Aim 3 employs a yeast two- hybrid approach with the """"""""Nrl-bZIP bait"""""""" to identify the proteins that productively heterodimerize with Nrl and may be involved in regulating different sets of genes in the retina. The long-term objective of P.I.'s research is to understand the molecular events involved in the pathogenesis of eye diseases and eventually assist in the design of gene-based therapeutic strategies. Transcription factors have become attractive targets for mechanism- based design of drugs, which can be used to modulate specific biochemical pathways. In that direction, the proposed studies are designed to identify transcriptional regulatory proteins that together with Nrl mediate tissue- or cell type- specific gene expression in the retina, and should provide mechanistic insights into the molecular basis of congenital and inherited retinal disorders.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
1R01EY011115-01A1
Application #
2019993
Study Section
Visual Sciences C Study Section (VISC)
Project Start
1996-12-01
Project End
1999-11-30
Budget Start
1996-12-01
Budget End
1997-11-30
Support Year
1
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Ophthalmology
Type
Schools of Medicine
DUNS #
791277940
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Cheng, Hong; Khan, Naheed W; Roger, Jerome E et al. (2011) Excess cones in the retinal degeneration rd7 mouse, caused by the loss of function of orphan nuclear receptor Nr2e3, originate from early-born photoreceptor precursors. Hum Mol Genet 20:4102-15
Parapuram, Sunil K; Cojocaru, Radu I; Chang, Jessica R et al. (2010) Distinct signature of altered homeostasis in aging rod photoreceptors: implications for retinal diseases. PLoS One 5:e13885
Kanda, Atsuhiro; Swaroop, Anand (2009) A comprehensive analysis of sequence variants and putative disease-causing mutations in photoreceptor-specific nuclear receptor NR2E3. Mol Vis 15:2174-84
Jia, Li; Oh, Edwin C T; Ng, Lily et al. (2009) Retinoid-related orphan nuclear receptor RORbeta is an early-acting factor in rod photoreceptor development. Proc Natl Acad Sci U S A 106:17534-9
Chrispell, Jared D; Feathers, Kecia L; Kane, Maureen A et al. (2009) Rdh12 activity and effects on retinoid processing in the murine retina. J Biol Chem 284:21468-77
Oh, Edwin C T; Cheng, Hong; Hao, Hong et al. (2008) Rod differentiation factor NRL activates the expression of nuclear receptor NR2E3 to suppress the development of cone photoreceptors. Brain Res 1236:16-29
Feathers, Kecia L; Lyubarsky, Arkady L; Khan, Naheed W et al. (2008) Nrl-knockout mice deficient in Rpe65 fail to synthesize 11-cis retinal and cone outer segments. Invest Ophthalmol Vis Sci 49:1126-35
Merienne, Karine; Friedman, James; Akimoto, Masayuki et al. (2007) Preventing polyglutamine-induced activation of c-Jun delays neuronal dysfunction in a mouse model of SCA7 retinopathy. Neurobiol Dis 25:571-81
Oh, Edwin C T; Khan, Naheed; Novelli, Elena et al. (2007) Transformation of cone precursors to functional rod photoreceptors by bZIP transcription factor NRL. Proc Natl Acad Sci U S A 104:1679-84
Swain, Prabodha; Kumar, Sandeep; Patel, Dharmesh et al. (2007) Mutations associated with retinopathies alter mitogen-activated protein kinase-induced phosphorylation of neural retina leucine-zipper. Mol Vis 13:1114-20

Showing the most recent 10 out of 57 publications