title: A domain directly C-terminal to the major homology region of human immunodeficiency type 1 capsid protein plays a crucial role in directing both virus assembly and incorporation of Gag-Pol.
abstract: We demonstrate here that a deletion of 14 amino acid residues directly C-terminal to the major homology region (MHR) of the HIV-1 capsid (CA) in Gag-Pol markedly affects the incorporation of Gag-Pol into virions. The 14-amino acid deletion also significantly impaired virus assembly. In agreement with previous reports, mutations at the very C-terminus of CA resulted in a remarkable reduction in virus production. However, HIV-1 Gag-Pol precursors containing the C-terminal CA mutation were still capable of being incorporated into virions at a level of about 50% that of the wild-type. These results suggest that the domain immediately C-terminal to the MHR is functionally involved in Gag-Gag and Gag/Gag-Pol interaction, and this supports the notion that Gag or Gag-Pol mutants blocked in assembly into virus particles can be rescued into virions provided they retain the domains that are able to interact with the Gag precursor. An HIV-1 Gag-Pol deletion mutant retaining a minimal sequence consisting of the MHR and the adjacent CA-SP1 was efficiently incorporated into virions. Analysis by immunofluorescence staining indicated that the subcellular localization patterns shown by the Gag-Pol mutants were not fully compatible with their efficiency in being incorporated into virions, suggesting that the ability of Gag-Pol mutants to be incorporated into virions largely depends on their interactions with the Gag precursor.
authors.affiliation: Department of Medical Research and Education, Taipei Veterans General Hospital, 201, Sec. 2, Shih-Pai Road, Taipei 11217, Taiwan.
authors.forename: An-I
authors.initials: AI
authors.lastname: Chien
authors.forename: Wei-Hao
authors.initials: WH
authors.lastname: Liao
authors.forename: De-Ming
authors.initials: DM
authors.lastname: Yang
authors.forename: Chin-Tien
authors.initials: CT
authors.lastname: Wang
mesh_terms: D015153:Blotting, Western; D036022:Capsid Proteins / Q000235:genetics* / Q000502:physiology*; D002460:Cell Line; D015683:Gene Products, gag / Q000378:metabolism*; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D008856:Microscopy, Fluorescence; D011498:Protein Precursors / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000235:genetics / Q000502:physiology; D017384:Sequence Deletion; D014764:Viral Proteins / Q000032:analysis; D019065:Virus Assembly; D054301:gag Gene Products, Human Immunodeficiency Virus; D054302:pol Gene Products, Human Immunodeficiency Virus
chemical_list: D036022:Capsid Proteins; D015683:Gene Products, gag; D011498:Protein Precursors; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; C059767:p55 gag precursor protein, Human immunodeficiency virus 1; D054302:pol Gene Products, Human Immunodeficiency Virus; C091950:pr160 gag-pol precursor protein, Human immunodeficiency virus 1