       Document 0838
 DOCN  M9550838
 TI    Growth and developmental functions of a human immunodeficiency virus
       Tat-binding protein/26S protease subunit homolog from Dictyostelium
       discoideum.
 DT    9505
 AU    Cao JG; Firtel RA; Department of Biology, University of California at
       San Diego, La; Jolla 92093-0634.
 SO    Mol Cell Biol. 1995 Mar;15(3):1725-36. Unique Identifier : AIDSLINE
       MED/95166258
 AB    We have characterized a newly identified gene from Dictyostelium
       discoideum, DdTBP alpha, that encodes a member of the family of
       eukaryotic proteins. These proteins contain a conserved ATPase domain,
       include subunits of the 26S protease subunit, and are homologous to the
       mammalian human immunodeficiency virus Tat-binding protein TBP1. While
       information indicates that some family members are involved in the
       regulation of transcription in mammalian and yeast cells during growth,
       these proteins are also involved in other cellular functions, and
       nothing is known about their possible function in multicellular
       development. The Dictyostelium DdTBP alpha gene is developmentally
       regulated, with its expression at the highest levels occurring during
       growth and early development. The gene is present in two copies in the
       genome. Disruption of one copy by homologous recombination leads to
       aberrant morphogenesis, which lasts from the formation of the first
       finger until the onset of culmination. The gene appears to be essential
       for growth since we were unable to obtain a complete null phenotype and
       since expression of an inducible antisense construct in the partial null
       background resulted in cell death. Expression of the antisense construct
       during development accentuated the partial null phenotype and also
       resulted in very abnormal fruiting bodies. Overexpression of DdTBP alpha
       from its own promoter leads to very large multinucleated vegetative
       cells when the cells are grown in suspension culture. When the cells are
       plated onto petri dishes in growth medium, they rapidly split into
       multiple cells containing one to two nuclei, in a manner similar to that
       of wild-type cells. Overexpressing cells are significantly delayed in
       forming a multicellular aggregate, but development proceeds normally
       once the first finger stage is reached. The results indicate that DdTBP
       alpha plays an important role in regulating both growth and
       morphogenesis in D. discoideum.
 DE    Adenosinetriphosphatase/GENETICS  Amino Acid Sequence  Animal  Cell
       Division  Cloning, Molecular  Comparative Study  Conserved Sequence
       Dictyostelium/CYTOLOGY/*GENETICS/METABOLISM  Gene Expression  Gene
       Products, tat/*GENETICS  Genes, Fungal  Genomic Library
       HIV/*GENETICS/METABOLISM  Kinetics  Macromolecular Systems  Molecular
       Sequence Data  Peptide Hydrolases/BIOSYNTHESIS/*GENETICS/ISOLATION &
       PURIF  Promoter Regions (Genetics)  Recombinant
       Proteins/BIOSYNTHESIS/ISOLATION & PURIF  Restriction Mapping  Sequence
       Homology, Amino Acid  Support, U.S. Gov't, P.H.S.  JOURNAL ARTICLE

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

