Albumin and alpha-fetoprotein (AFP), adjacent members of a gene family, are critical markers of developmental and neoplastic phenotypes in hepatocytes. Studies suggest that the two genes are coordinately regulated through common transcription controls. The AFP gene is regulated by long-distance coupling mediated by a novel transcription factor, PCF; the albumin gene shows similar long-distance stimulation, but not mediated by PCF. The goal of this study is to characterize the unique coupling elements that regulate the albumin-AFP locus and to demonstrate that these elements are integral components of the local chromosomal organization. Toward this goal, Aim 1 experiments will define the element(s) between -170 and -84 in the albumin promoter which is responsive to the enhancers within the AFP gene. Deletion and mutation studies will localize significant elements, oligonucleotide gel shift experiments will characterize the essential transcription factors, and new factors defined by this approach will be cloned from a lambda gt expression library.
In Aim 2, studies are primarily focused upon identifying whether Matrix Association Regions (MARs), sites of chromosomal attachment to the nuclear scaffold, are present within the region from -15 of the albumin gene to +10 of the AFP gene.
Aim 3 experiments will focus on studying how the entire albumin/AFP locus functions as a single unit in stably transfected cells with the control elements placed at correct genomic locations. Plasmids will be generated to establish a second model system for the study of long-distance gene regulation within a chromosomal locus with properties very different from the beta globin locus.
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