A multidrug resistance transporter/serine protease gene is required for prestalk specialization in Dictyostelium.
The prestalk-specific gene, tagB, was disrupted by restriction enzyme-mediated integration (REMI) mutagenesis. Mutant aggregates exhibit a cell-autonomous defect in specialization of PST-A cells, a prestalk subpopulation that forms the tip and eventually forms the stalk of the fruiting body. Cooperative (non-cell-autonomous) defects were found in sporulation and in specialization of prestalk cells that eventually form the upper cup of the fruiting body (PST-O). The pattern of ecmA::lacZ expression in mutant tagB- cells defines a primary prestalk population, PST-I, from which other prestalk cells differentiate. After PST-A cells differentiate, they induce remaining PST-I cells to become PST-O cells. Subsequently, prestalk cells induce encapsulation of prespore cells during culmination. tagB is homologous to serine protease and to multidrug resistance (MDR) transporter genes, implying a mechanism of action that includes proteolysis and export of peptide signals. Intercellular communication via TagB may mediate integration of cellular differentiation with morphogenesis.
Shaulsky
G
G
Department of Biology, University of California, San Diego, La Jolla 92093, USA.
Kuspa
A
A
Loomis
W F
WF
D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D002454:Cell Differentiation; D003001:Cloning, Molecular; D004023:Dictyostelium / Q000166:cytology / Q000235:genetics* / Q000254:growth & development*; D018432:Drug Resistance, Multiple / Q000235:genetics*; D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005800:Genes, Fungal / Q000235:genetics*; D006588:Hexanones / Q000378:metabolism / Q000494:pharmacology; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000379:methods; D015800:Protozoan Proteins; D012331:RNA, Fungal / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*
D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D005656:Fungal Proteins; D006588:Hexanones; D015800:Protozoan Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C053433:1-((3,5-dichloro)-2,6-dihydroxy-4-methoxyphenyl)-1-hexanone; C093527:TagB protein, Dictyostelium; D012697:Serine Endopeptidases