Chromosomal Elements Regulate Gene Activity and Chromatin Structure of the Human Serpin Gene Cluster at 14q32.1

Abstract

ABSTRACT The human serine protease inhibitor (serpin) gene cluster at 14q32.1 contains a number of genes that are specifically expressed in hepatic cells. Cell-specific enhancers have been identified in several of these genes, but elements involved in locus-wide gene and chromatin control have yet to be defined. To identify regulatory elements in this region, we prepared a series of mutant chromosomal alleles by homologous recombination and transferred the specifically modified human chromosomes to hepatic cells for functional tests. We report that deletion of an 8-kb DNA segment upstream of the human α1-antitrypsin gene yields a mutant serpin allele that fails to be activated in hepatic cells. Within this region, a 2.3-kb DNA segment between kb −8.1 and −5.8 contains a previously unrecognized control region that is required not only for serpin gene activation but also for chromatin remodeling of the entire locus.