title: Cloning of the mouse fusin gene, homologue to a human HIV-1 co-factor.
abstract: Previous studies have demonstrated that mouse cells do not become infected with HIV-1 despite transfection with human CD4. Recently, a human protein termed "fusin" with characteristics of a seven-transmembrane-spanning receptor was found to be a co-factor required for the entry and fusion of HIV-1 with human CD4-bearing lymphocytes. Thus, cloning of the murine homologue of the human fusin (also termed CXCR-4) gene could provide an important comparative tool for identification of the structures crucial for fusin function. Using degenerate PCR, the mouse homologue of human fusin was cloned from a peritoneal exudate cell cDNA library. The predicted amino acid sequence is 91% identical to human fusin. Twenty-eight of the 37 amino acid differences between mouse and human fusin are located in the ectodomains, suggesting that the intracytoplasmic components that mediate G protein binding and signaling are highly conserved. Northern blot analysis showed a message of 2.2 kb in thymus, spleen, neutrophils, and primary astrocyte cultures. Lymphoid and monocyte cell lines also expressed message for fusin. The coding regions of most chemokine receptors lack introns. In contrast, cloning of genomic DNA for mouse fusin revealed the presence of a 2.3-Kb intron separating the first seven amino acids from the remaining 352 residues. Therefore, the mouse fusin gene has a unique genomic organization compared with other chemokine receptors.
authors.affiliation: Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: M
authors.initials: M
authors.lastname: Heesen
authors.forename: M A
authors.initials: MA
authors.lastname: Berman
authors.forename: J D
authors.initials: JD
authors.lastname: Benson
authors.forename: C
authors.initials: C
authors.lastname: Gerard
authors.forename: M E
authors.initials: ME
authors.lastname: Dorf
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D015870:Gene Expression; D005796:Genes; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D019718:Receptors, CXCR4; D015728:Receptors, HIV / Q000235:genetics*; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid
chemical_list: D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D019718:Receptors, CXCR4; D015728:Receptors, HIV