title: Structure, organization, and chromosomal mapping of the human macrophage scavenger receptor gene.
abstract: Macrophage scavenger receptors (MSR) mediate the binding, internalization, and processing of a wide range of negatively charged macromolecules. Functional MSR are trimers of two C-terminally different subunits that contain six functional domains. We have cloned an 80-kilobase human MSR gene and localized it to band p22 on chromosome 8 by fluorescent in situ hybridization and by genetic linkage using three common restriction fragment length polymorphisms. The human MSR gene consists of 11 exons, and two types of mRNAs are generated by alternative splicing from exon 8 to either exon 9 (type II) or to exons 10 and 11 (type I). The promoter has a 23-base pair inverted repeat with homology to the T cell element. Exon 1 encodes the 5'-untranslated region followed by a 12-kilobase intron which separates the transcription initiation and the translation initiation sites. Exon 2 encodes a cytoplasmic domain, exon 3, a transmembrane domain, exons 4 and 5, an alpha-helical coiled-coil, and exons 6-8, a collagen-like domain. The position of the gap in the coiled coil structure corresponds to the junction of exons 4 and 5. These results show that the human MSR gene consists of a mosaic of exons that encodes the functional domains. Furthermore, the specific arrangement of exons played a role in determining the structural characteristics of functional domains.
authors.affiliation: Department of Biosciences, National Cardiovascular Center Research Institute, Osaka, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Emi
authors.forename: H
authors.initials: H
authors.lastname: Asaoka
authors.forename: A
authors.initials: A
authors.lastname: Matsumoto
authors.forename: H
authors.initials: H
authors.lastname: Itakura
authors.forename: Y
authors.initials: Y
authors.lastname: Kurihara
authors.forename: Y
authors.initials: Y
authors.lastname: Wada
authors.forename: H
authors.initials: H
authors.lastname: Kanamori
authors.forename: Y
authors.initials: Y
authors.lastname: Yazaki
authors.forename: E
authors.initials: E
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Lepert
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D002898:Chromosomes, Human, Pair 8; D003001:Cloning, Molecular; D004247:DNA / Q000737:chemistry / Q000235:genetics; D005091:Exons; D006023:Glycoproteins / Q000737:chemistry* / Q000235:genetics*; D006801:Humans; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D012150:Polymorphism, Restriction Fragment Length; D011401:Promoter Regions, Genetic; D017433:Protein Structure, Secondary; D012326:RNA Splicing; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000235:genetics*; D011971:Receptors, Immunologic; D051116:Receptors, Scavenger; D051117:Scavenger Receptors, Class A; D014158:Transcription, Genetic
chemical_list: D006023:Glycoproteins; C495139:MSR1 protein, human; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; D051116:Receptors, Scavenger; D051117:Scavenger Receptors, Class A; D004247:DNA