Temperature-Sensitive Inhibition of Development in Dictyostelium Due to a Point Mutation in the piaA Gene

Developmental Biology

Adriano Ceccarelli¹  Angelika Noegel¹  Salvatore Bozzaro¹  Barbara Pergolizzi¹  Peter Devreotes¹  James Silverman¹  Barbara Peracino¹ 

[1] Dipartimento di Scienze Cliniche e Biologiche, Università di Torino, Ospedale S. Luigi, 10043, Orbassano, Italy

关键词: adenylyl cyclase;    chemotaxis;    Dictyostelium;    G protein;    signal transduction;    slime molds;   

DOI  :  10.1006/dbio.2002.0809

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

TheDictyosteliummutantHSB1istemperature-sensitivefordevelopment,undergoingaggregationandfruitingbodyformationattemperaturesbelow18°Cbutnotabove.InvivoGprotein-linkedadenylylcyclaseactivationisdefectiveinHSB1,andtheenzymeisnotstimulatedinvitrobyGTPγS;stimulationisrestoreduponadditionofwild-typecytosol.TransfectionwiththegeneencodingthecytosolicregulatorPIArescuedthemutant.WeexcludedthepossibilitythatHSB1cellsfailtoexpressPIAandshowthattheHSB1piaAgeneharborsapointmutation,resultingintheaminoacidexchangeG917D.Bothwild-typeandHSB1cellswerealsotransfectedwiththeHSB1piaAgene.ThepiaAHSB1geneproductdisplayedapartialinhibitoryeffectonwild-typecelldevelopment.WehypothesizethatPIAcouplestheheterotrimericGproteintoadenylylcyclaseviatwobindingsites,oneofwhichisalteredinatemperature-sensitivewaybytheHSB1mutation.Whenoverexpressedinthewild-typebackground,PIAHSB1competeswithwild-typePIAviathenonmutatedbindingsite,resultingindominant-negativeinhibitionofdevelopment.ExpressionofGFP-fusedPIAshowsthatPIAishomogeneouslydistributedinthecytoplasmofchemotacticallymovingcells.

【 授权许可】

Unknown