Document 0095
 DOCN  M9460095
 TI    The Bel1 protein of human foamy virus contains one positive and two
       negative control regions which regulate a distinct activation domain of
       30 amino acids.
 DT    9404
 AU    Lee CW; Chang J; Lee KJ; Sung YC; Department of Life Science, Pohang
       University of Science and; Technology, Korea.
 SO    J Virol. 1994 Apr;68(4):2708-19. Unique Identifier : AIDSLINE
       MED/94187112
 AB    The Bel1 transactivator is essential for the replication of human foamy
       virus (HFV). To define the functional domains of HFV Bel1, we generated
       random missense mutations throughout the entire coding sequence of Bel1.
       Functional analyses of 24 missense mutations have revealed the presence
       of at least two functional domains in Bel1. One domain corresponds to a
       basic amino acid-rich motif which acts as a bipartite nuclear targeting
       sequence. A second, central domain corresponds to a presumed effector
       region which, when mutated, leads to dominant-negative mutants and/or
       lacks transactivating ability. In addition, deletion analyses and
       domain-swapping experiments further showed that Bel1 protein contains a
       strong carboxy-terminal activation domain. The activating region is also
       capable of functioning as a transcription-activating domain in yeast
       cells, although it does not bear any significant sequence homology to
       the well-characterized acidic activation domain which is known to
       function only in yeast and mammalian cells. We also demonstrated that
       the regions of Bel1 from residues 1 to 76 and from residues 153 to 225
       repressed transcriptional activation exerted by the Bel1 activation
       domain. In contrast, the region from residues 82 to 150 appears to
       overcome an inhibitory effect. These results indicate that Bel1 contains
       one positive and two negative regulatory domains that modulate a
       distinct activation domain of Bel1. These regulatory domains of Bel1
       cannot affect the function of the VP16 activation domain, suggesting
       that these domains specifically regulate the activation domain of Bel1.
       Furthermore, in vivo competition experiments showed that the positive
       regulatory domain acts in trans. Thus, our results demonstrate that
       Bel1-mediated transactivation appears to undergo a complex regulatory
       pathway which provides a novel mode of regulation for a transcriptional
       activation domain.
 DE    Amino Acid Sequence  Animal  Antibodies, Viral  Base Sequence  Cell
       Compartmentation  Chimeric Proteins  DNA Mutational Analysis
       DNA-Binding Proteins/*GENETICS/IMMUNOLOGY/ISOLATION & PURIF  Fluorescent
       Antibody Technique  Human  HIV Long Terminal Repeat/GENETICS
       HIV-1/GENETICS  Models, Genetic  Molecular Sequence Data  Mutagenesis,
       Site-Directed  Repetitive Sequences, Nucleic Acid/GENETICS  Retroviridae
       Proteins/*GENETICS/IMMUNOLOGY/ISOLATION & PURIF  Saccharomyces
       cerevisiae/GENETICS  Spumavirus/*GENETICS  Support, Non-U.S. Gov't
       *Trans-Activation (Genetics)
       Trans-Activators/*GENETICS/IMMUNOLOGY/ISOLATION & PURIF  Transfection
       Transformation, Genetic  JOURNAL ARTICLE

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