Abstract: The targeted disruption of the gene encoding the heme-regulated eIF2-kinase (HRI) in mice establishes that HRI, which is expressed predominantly in erythroid cells, regulates the synthesis of both alpha and beta globins in red blood cell precursors by inhibiting the general translation initiation factor eIF2. HRI is a physiological regulator of gene expression in the erythroid lineage and acts both as a sensor of heme and an effector controlling the initiation of translation. Accordingly regulation of HRI can be used to control proliferation of cells, especially cells of hematopoietic origin, using compositions and compounds identified using HRI deficient mice.

Abstract: The cDNA which encodes heme-regulated eIF-2.alpha. kinase (HRI) has been cloned from a lambda Zap II cDNA library of rabbit reticulocytes. The rabbit HRI cDNA is highly homologous to human HRI and hybridizes to the human HRI DNA under moderately stringent conditions. The rabbit HRI cDNA contains 2729 amino acids. In vitro translation of HRI mRNA transcribed from HRI cDNA yields a 90 kDa polypeptide with eIF-2.alpha. kinase activity. Since HRI is a potent inhibitor of protein synthesis, it is anti-proliferative in nature. In addition, the unusually high degree of homology of HRI to three protein kinases involved in the regulation of cell division suggests that HRI plays a direct role in the regulation of cell division.

Abstract: The cDNA which encodes heme-regulated eIF-2.alpha. kinase (HRI) has been cloned from a lambda Zap II cDNa of rabbit reticulocytes. The rabbit HRI cDNA is highly homologous to human HRI and hybridizes to the human HRI DNA under moderately stringent conditions. The rabbit HRI cDNA contains 2729 amino acids. In vitro translation of HRI mRNA transcribed from HRI cDNA yields a 90 kDa polypeptide with eIF-2.alpha. kinase activity. Since HRI is a potent inhibitor or protein synthesis, it is anti-proliferative in nature. In addition, the unusually high degree of homology of HRI to three protein kinases involved in the regulation of cell division suggests that HRI plays a direct role in the regulation of cell division.