A G-protein beta-subunit is essential for Dictyostelium development.
Recent studies have demonstrated that G-protein-linked signal transduction pathways play a significant role in the developmental program of the simple eukaryotic organism Dictyostelium. We have reported previously the isolation of a G-protein beta-subunit and present here a more complete analysis of this gene. Low-stringency Southern blots and RFLP mapping studies suggest that the beta-subunit is a unique gene found on linkage group II. Its deduced amino acid sequence of 347 residues is approximately 60% identical to those of the human, Drosophila, and Caenorhabditis elegans beta-subunits. The carboxy-terminal 300 residues are about 70% identical; the amino-terminal 50 residues are quite divergent, containing only 10 identities. At all stages of growth and development, a single 1.9-kb beta-subunit mRNA is present at a high level, and a specific antibody detects a single 37-kD protein. We propose that G-protein heterotrimers are formed when this beta-subunit couples with each of the eight distinct G-protein alpha-subunits that are transiently expressed during development. Targeted disruption of the beta-subunit gene had no effect on the viability of haploid cells, but resulted in the inability of cells to aggregate.
Lilly
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P
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2185.
Wu
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Welker
D L
DL
Devreotes
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PN
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D016373:DNA, Antisense / Q000235:genetics; D004271:DNA, Fungal / Q000032:analysis / Q000737:chemistry; D016054:DNA, Protozoan / Q000032:analysis / Q000737:chemistry; D004023:Dictyostelium / Q000235:genetics / Q000254:growth & development*; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009841:Oligonucleotides / Q000737:chemistry; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D012150:Polymorphism, Restriction Fragment Length; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D016373:DNA, Antisense; D004271:DNA, Fungal; D016054:DNA, Protozoan; D009841:Oligonucleotides; D010446:Peptide Fragments; D019204:GTP-Binding Proteins