Document 0900
 DOCN  M9470900
 TI    Molecular biology of human herpesviruses 6A and 6B.
 DT    9409
 AU    Inoue N; Dambaugh TR; Pellett PE; Centers for Disease Control and
       Prevention, Atlanta, Georgia; 30333.
 SO    Infect Agents Dis. 1993 Dec;2(6):343-60. Unique Identifier : AIDSLINE
       MED/94282499
 AB    Human herpesvirus 6 variant A (HHV-6A) and human herpesvirus 6 variant B
       (HHV-6B) are closely related herpesviruses. No disease has been
       specifically associated with HHV-6A, whereas HHV-6B is the major
       etiologic agent of exanthem subitum. Both viruses may be opportunistic
       pathogens in the immunocompromised patient. HHV-6 genomes have low G+C
       contents for herpesviruses (43%); they consist of a 141-kb unique
       segment that is flanked by single copies of a directly repeated sequence
       that can vary from 10 to 13 kb. HHV-6A and HHV-6B encode homologs of
       many conserved herpesvirus proteins and are classified as
       beta-herpesviruses based on their close genetic relationship with human
       cytomegalovirus. HHV-6A and HHV-6B are even more closely related to the
       recently discovered human herpesvirus 7. HHV-6 encodes homologs of the
       seven genes that are essential for origin-dependent herpes simplex virus
       type 1 DNA replication, including the origin-binding protein, which has
       no clear homolog in human cytomegalovirus. The HHV-6B origin-binding
       protein binds to sequences with similarities to alpha-herpesvirus
       replication origins that lie within a genomic segment that can serve as
       a replication origin in transient replication assays. Both HHV-6
       variants encode homologs of the adeno-associated virus type 2 Rep
       protein; the role of this protein during infection is unknown. HHV-6
       induces synthesis of a broad range of host cell proteins, including
       interferon alpha, CD4, interleukin-1 beta, and tumor necrosis factor
       alpha, and also induces expression of the human immunodeficiency virus
       type 1 LTR promoter. Little is known about the process by which HHV-6
       regulates gene expression.
 DE    Animal  Bacterial Proteins/GENETICS  Base Sequence
       Dependovirus/GENETICS  DNA Replication  DNA,
       Viral/BIOSYNTHESIS/METABOLISM  Gene Expression Regulation, Viral  Genes,
       Viral  *Genome, Viral  Herpesvirus 6, Human/*GENETICS/PATHOGENICITY
       Human  Molecular Sequence Data  Repetitive Sequences, Nucleic Acid
       Trans-Activation (Genetics)  Transcription, Genetic  Viral Structural
       Proteins/GENETICS  Virus Replication  JOURNAL ARTICLE  REVIEW  REVIEW,
       ACADEMIC

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).