Atopic dermatitis (AD) and psoriasis are two inflammatory skin diseases that affect over 22.5 million Americans collectively and are burdening the U.S. economy with over $7.5 billion dollars in management and quality-of-life issue costs. These diseases share linkage to the epidermal differentiation complex (EDC) on chromosome 1q21. The EDC spans 1.6Mb and contains a majority of genes that are specifically expressed upon terminal differentiation of the epidermis and subsequent skin barrier formation. The proximity and density of these genes on 1q21 suggest coordinate regulation via cis-regulatory elements. To date, only a few regulatory elements have been identified in the EDC. My goal is to identify enhancers that control gene expression in the EDC. Using comparative multi-species sequence analysis, we hypothesize that evolutionarily conserved noncoding sequences (CNS) function as enhancers to coordinate transcriptional regulation of genes within the EDC. To test this hypothesis, we propose the following 2 aims:
In Specific Aim 1, we will test the function of the CNS to direct in vitro enhancer activity using luciferase reporter assays in mouse epidermal cells.
In Specific Aim 2 A, we will determine colocalization of the CNS EDC to open chromatin using DNasel hypersensitivity assays in mouse keratinocytes and barrier deficient mouse models.
These aims will be completed during the mentored phase under Dr. Julie Segre at the National Human Genome Research Institute (NHGRI) in Bethesda, MD. The following aims will be pursued during the independent phase under the bridge mentorship of Dr. Anne Bowcock from Washington University:
In Specific Aim 2 B, we will also determine if these CNS EDC map to regions bound by p300 and monomethylated H3K4 enriched in enhancer sequences using chromatin immunoprecipitation (ChIP).
In Specific Aim 3, will assess transcription factor binding to the CNS EDC using bioinformatics and ChIP.
In Specific Aim 4, we will test select CNS EDC in vivo as epidermal locus control regions using CNS EDC- hsp68-lacZ transgenic mice. This proposal functions as Cristina de Guzman Strong's career development plan in obtaining an independent research position at an academic institution. Results from the research plan will shed light on the genetic and epigenetic mechanisms underlying epidermal differentiation and barrier formation as well contribute to our understanding of atopic dermatitis and psoriasis.
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