title: The human lamin B receptor/sterol reductase multigene family.
abstract: LBR (lamin B receptor) is an integral protein of the inner nuclear membrane encoded by a gene on human chromosome 1q42.1. LBR has a nucleoplasmic, amino-terminal domain of approximately 200 amino acids followed by a carboxyl-terminal domain similar in sequence to yeast and plant sterol reductases. We have determined the primary structures of two human proteins with strong sequence similarity to the carboxyl-terminal domain of LBR and sterol reductases. Their genes have recently been assigned the symbols TM7SF2 and DHCR7. TM7SF2 mRNA is most predominantly expressed in heart and DHCR7 mRNA mostly in liver and brain. Whereas LBR is localized to the inner nuclear membrane, these two related proteins are in the endoplasmic reticulum. The TM7SF2 gene contains 10 coding exons, and its intron positions are exactly conserved in the part of the LBR gene encoding its carboxyl-terminal domain. Intron positions in the DHCR7 gene are also similar. Both of these new LBR-like genes are on chromosome 11q13. These results describe a human gene family encoding proteins of the inner nuclear membrane and endoplasmic reticulum that function in nuclear organization and/or sterol metabolism.
authors.affiliation: Department of Anatomy and Cell Biology, College of Physicians and Surgeons, New York, New York, 10032, USA.
authors.forename: L
authors.initials: L
authors.lastname: Holmer
authors.forename: A
authors.initials: A
authors.lastname: Pezhman
authors.forename: H J
authors.initials: HJ
authors.lastname: Worman
mesh_terms: D000595:Amino Acid Sequence; D002880:Chromosomes, Human, Pair 11; D003001:Cloning, Molecular; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D010088:Oxidoreductases / Q000235:genetics*; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010940:Plant Proteins / Q000235:genetics; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D000097682:Lamin B Receptor
chemical_list: D005656:Fungal Proteins; D008565:Membrane Proteins; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010940:Plant Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D000097682:Lamin B Receptor; C019995:7-dehydrocholesterol reductase; C113387:TM7SF2 protein, human