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Two orphan seven-transmembrane segment receptors which are expressed in CD4-positive cells support simian immunodeficiency virus infection.

Farzan M, Choe H, Martin K, Marcon L, Hofmann W, Karlsson G, Sun Y, Barrett P, Marchand N, Sullivan N, Gerard N, Gerard C, Sodroski J - J. Exp. Med. (1997)

Bottom Line: The more efficient of these, gpr15, is also expressed in human CD4(+) T lymphocytes and activated rhesus macaque peripheral blood mononuclear cells.The gpr15 and gpr1 proteins lack several hallmarks of chemokine receptors, but share with CCR5 an amino-terminal motif rich in tyrosine residues.These results underscore the potential diversity of seven-transmembrane segment receptors used as entry cofactors by primate immunodeficiency viruses, and may contribute to an understanding of viral variation and pathogenesis.

View Article: PubMed Central - PubMed

Affiliation: Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.

ABSTRACT
Clinical isolates of primate immunodeficiency viruses, including human immunodeficiency virus type 1 (HIV-1), enter target cells by sequential binding to CD4 and the chemokine receptor CCR5, a member of the seven-transmembrane receptor family. HIV-1 variants which use additional chemokine receptors are present in the central nervous system or emerge during the course of infection. Simian immunodeficiency viruses (SIV) have been shown to use CCR5 as a coreceptor, but no other receptors for these viruses have been identified. Here we show that two orphan seven-transmembrane segment receptors, gpr1 and gpr15, serve as coreceptors for SIV, and are expressed in human alveolar macrophages. The more efficient of these, gpr15, is also expressed in human CD4(+) T lymphocytes and activated rhesus macaque peripheral blood mononuclear cells. The gpr15 and gpr1 proteins lack several hallmarks of chemokine receptors, but share with CCR5 an amino-terminal motif rich in tyrosine residues. These results underscore the potential diversity of seven-transmembrane segment receptors used as entry cofactors by primate immunodeficiency viruses, and may contribute to an understanding of viral variation and pathogenesis.

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CAT activity in Cf2Th cells expressing CD4 alone or together with gpr1, gpr15, CCR5, or CXCR4 after incubation with HIV-1 recombinant viruses carrying the SIVmac239, SIVmac316, or HIV-1 (YU2, HXBc2, 89.6, or ADA) envelope glycoproteins. A representative experiment is shown.  The amount of target cell lysate used was equivalent for all the experiments shown. CAT activity was determined by calculating the percentage of  chloramphenicol present in acetylated forms (three uppermost spots) to the total amount of chloramphenicol. The nonacetylated form of chloramphenicol is  present in the spot closest to the origin, which is near the bottom of the figure.
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Figure 1: CAT activity in Cf2Th cells expressing CD4 alone or together with gpr1, gpr15, CCR5, or CXCR4 after incubation with HIV-1 recombinant viruses carrying the SIVmac239, SIVmac316, or HIV-1 (YU2, HXBc2, 89.6, or ADA) envelope glycoproteins. A representative experiment is shown. The amount of target cell lysate used was equivalent for all the experiments shown. CAT activity was determined by calculating the percentage of chloramphenicol present in acetylated forms (three uppermost spots) to the total amount of chloramphenicol. The nonacetylated form of chloramphenicol is present in the spot closest to the origin, which is near the bottom of the figure.

Mentions: We had previously tested a number of human chemokine receptors (CCR1–CCR5, as well as CXCR4) and found that of these only CCR5 could support entry of an HIV-1 virus pseudotyped with the envelope glycoproteins of a pathogenic, molecularly cloned SIV, SIVmac239 (47). To identify additional coreceptors which might be used by SIV, we screened cDNA libraries from SIV-infectable cells, CEM×174 and U87, for the expression of mRNA encoding known 7-TMS proteins exhibiting some sequence similarity to chemokine receptors. The cDNAs which were shown to be expressed in either cell line were tested for the ability to support SIV and HIV-1 entry. Recombinant HIV-1 viruses which contained either HIV-1 or SIV envelope glycoproteins and expressed CAT were incubated with Cf2Th canine thymocytes transfected with plasmids expressing human CD4 and the 7-TMS proteins. Table 1 lists the 7-TMS proteins tested, summarizes their expression in CEM×174, U87, and human CD4+ T cells, and indicates coreceptor activity for viruses with the SIVmac239 envelope glycoproteins. Of the 7-TMS proteins tested, only gpr1, gpr15, and CCR5 supported the entry of viruses with the SIVmac239 envelope glycoproteins. These three 7-TMS proteins also supported the entry of viruses with the macrophage-tropic SIVmac316 envelope glycoproteins (Fig. 1). The SIV coreceptor activity exhibited by the gpr15 protein was greater than that of CCR5, whereas the coreceptor activity of gpr1 was ∼30% that of CCR5 (Table 2). Most of the viruses with HIV-1 envelope glycoproteins (HXBc2, JR-FL, 89.6) did not infect Cf2Th cells expressing CD4 and gpr15, although the viruses with the M-tropic HIV-1 ADA and YU2 envelope glycoproteins demonstrated a low but reproducible signal in these cells (Fig. 1 and Table 2). Following incubation with the ADA and YU2 viruses, the CAT conversion in the CD4+, gpr15+ Cf2Th cells was <1% of that seen in the CD4+, CCR5+ control cells (Table 2). Cf2Th cells expressing CD4 and gpr1 were not infected by viruses containing any of the HIV-1 envelope glycoproteins tested (Table 2).


Two orphan seven-transmembrane segment receptors which are expressed in CD4-positive cells support simian immunodeficiency virus infection.

Farzan M, Choe H, Martin K, Marcon L, Hofmann W, Karlsson G, Sun Y, Barrett P, Marchand N, Sullivan N, Gerard N, Gerard C, Sodroski J - J. Exp. Med. (1997)

CAT activity in Cf2Th cells expressing CD4 alone or together with gpr1, gpr15, CCR5, or CXCR4 after incubation with HIV-1 recombinant viruses carrying the SIVmac239, SIVmac316, or HIV-1 (YU2, HXBc2, 89.6, or ADA) envelope glycoproteins. A representative experiment is shown.  The amount of target cell lysate used was equivalent for all the experiments shown. CAT activity was determined by calculating the percentage of  chloramphenicol present in acetylated forms (three uppermost spots) to the total amount of chloramphenicol. The nonacetylated form of chloramphenicol is  present in the spot closest to the origin, which is near the bottom of the figure.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2198994&req=5

Figure 1: CAT activity in Cf2Th cells expressing CD4 alone or together with gpr1, gpr15, CCR5, or CXCR4 after incubation with HIV-1 recombinant viruses carrying the SIVmac239, SIVmac316, or HIV-1 (YU2, HXBc2, 89.6, or ADA) envelope glycoproteins. A representative experiment is shown. The amount of target cell lysate used was equivalent for all the experiments shown. CAT activity was determined by calculating the percentage of chloramphenicol present in acetylated forms (three uppermost spots) to the total amount of chloramphenicol. The nonacetylated form of chloramphenicol is present in the spot closest to the origin, which is near the bottom of the figure.
Mentions: We had previously tested a number of human chemokine receptors (CCR1–CCR5, as well as CXCR4) and found that of these only CCR5 could support entry of an HIV-1 virus pseudotyped with the envelope glycoproteins of a pathogenic, molecularly cloned SIV, SIVmac239 (47). To identify additional coreceptors which might be used by SIV, we screened cDNA libraries from SIV-infectable cells, CEM×174 and U87, for the expression of mRNA encoding known 7-TMS proteins exhibiting some sequence similarity to chemokine receptors. The cDNAs which were shown to be expressed in either cell line were tested for the ability to support SIV and HIV-1 entry. Recombinant HIV-1 viruses which contained either HIV-1 or SIV envelope glycoproteins and expressed CAT were incubated with Cf2Th canine thymocytes transfected with plasmids expressing human CD4 and the 7-TMS proteins. Table 1 lists the 7-TMS proteins tested, summarizes their expression in CEM×174, U87, and human CD4+ T cells, and indicates coreceptor activity for viruses with the SIVmac239 envelope glycoproteins. Of the 7-TMS proteins tested, only gpr1, gpr15, and CCR5 supported the entry of viruses with the SIVmac239 envelope glycoproteins. These three 7-TMS proteins also supported the entry of viruses with the macrophage-tropic SIVmac316 envelope glycoproteins (Fig. 1). The SIV coreceptor activity exhibited by the gpr15 protein was greater than that of CCR5, whereas the coreceptor activity of gpr1 was ∼30% that of CCR5 (Table 2). Most of the viruses with HIV-1 envelope glycoproteins (HXBc2, JR-FL, 89.6) did not infect Cf2Th cells expressing CD4 and gpr15, although the viruses with the M-tropic HIV-1 ADA and YU2 envelope glycoproteins demonstrated a low but reproducible signal in these cells (Fig. 1 and Table 2). Following incubation with the ADA and YU2 viruses, the CAT conversion in the CD4+, gpr15+ Cf2Th cells was <1% of that seen in the CD4+, CCR5+ control cells (Table 2). Cf2Th cells expressing CD4 and gpr1 were not infected by viruses containing any of the HIV-1 envelope glycoproteins tested (Table 2).

Bottom Line: The more efficient of these, gpr15, is also expressed in human CD4(+) T lymphocytes and activated rhesus macaque peripheral blood mononuclear cells.The gpr15 and gpr1 proteins lack several hallmarks of chemokine receptors, but share with CCR5 an amino-terminal motif rich in tyrosine residues.These results underscore the potential diversity of seven-transmembrane segment receptors used as entry cofactors by primate immunodeficiency viruses, and may contribute to an understanding of viral variation and pathogenesis.

View Article: PubMed Central - PubMed

Affiliation: Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.

ABSTRACT
Clinical isolates of primate immunodeficiency viruses, including human immunodeficiency virus type 1 (HIV-1), enter target cells by sequential binding to CD4 and the chemokine receptor CCR5, a member of the seven-transmembrane receptor family. HIV-1 variants which use additional chemokine receptors are present in the central nervous system or emerge during the course of infection. Simian immunodeficiency viruses (SIV) have been shown to use CCR5 as a coreceptor, but no other receptors for these viruses have been identified. Here we show that two orphan seven-transmembrane segment receptors, gpr1 and gpr15, serve as coreceptors for SIV, and are expressed in human alveolar macrophages. The more efficient of these, gpr15, is also expressed in human CD4(+) T lymphocytes and activated rhesus macaque peripheral blood mononuclear cells. The gpr15 and gpr1 proteins lack several hallmarks of chemokine receptors, but share with CCR5 an amino-terminal motif rich in tyrosine residues. These results underscore the potential diversity of seven-transmembrane segment receptors used as entry cofactors by primate immunodeficiency viruses, and may contribute to an understanding of viral variation and pathogenesis.

Show MeSH
Related in: MedlinePlus