title: Characterization of the human gene encoding LBR, an integral protein of the nuclear envelope inner membrane.
abstract: We have characterized the human gene encoding LBR, an integral protein of the nuclear envelope inner membrane. Restriction mapping shows that the transcription unit spans approximately 35 kilobases. A transcription start site is located approximately 4 kilobases 5' to the translation initiation codon, and an RNA splice of 3863 bases occurs in the 5'-untranslated region to generate mature HeLa cell mRNA. 5' to the identified transcription start site are two CCAAT sequences and potential recognition sites for several transcription factors including Sp1, AP-1, AP-2, and NF-kB. There are 13 protein coding exons in the LBR gene. LBR's nucleoplasmic domain is encoded by exons 1-4, and its hydrophobic domain, with eight putative transmembrane segments, is encoded by exons 5-13. The hydrophobic domain is homologous to three yeast polypeptides, suggesting that this higher eukaryotic gene could have evolved from recombination between a gene that encoded a soluble nuclear protein and a membrane protein gene similar to those in yeast. These results are the first to demonstrate the structural organization of a vertebrate gene encoding an integral membrane protein of the nuclear envelope that may be a member of a family of polypeptides conserved in evolution.
authors.affiliation: Department of Medicine, Mount Sinai School of Medicine, New York, New York 10029.
authors.forename: E
authors.initials: E
authors.lastname: Schuler
authors.forename: F
authors.initials: F
authors.lastname: Lin
authors.forename: H J
authors.initials: HJ
authors.lastname: Worman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002645:Chickens; D003001:Cloning, Molecular; D017931:DNA Primers; D005091:Exons; D015698:Genomic Library; D006367:HeLa Cells; D015186:Hominidae / Q000235:genetics*; D006801:Humans; D007438:Introns; D008214:Lymphocytes / Q000378:metabolism; D008969:Molecular Sequence Data; D009685:Nuclear Envelope / Q000378:metabolism*; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis / Q000235:genetics*; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000378:metabolism; D000097682:Lamin B Receptor
chemical_list: D017931:DNA Primers; D009687:Nuclear Proteins; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D000097682:Lamin B Receptor