Cell-cell communication in the embryo of Caenorhabditis elegans☆

摘要

Wehaveinvestigatedthepatternofcell-cellcommunicationinembryosofthefree-livingsoilnematodeCaenorhabditiselegans.Forthis,wehaveestablishedamethodformicroinjectionoftracerdyesintoindividualblastomeres.Afteriontophoresisoffluorescentdyesofdifferentmolecularweights(Luciferyellow,LY,Mr457;rhodamine-labeleddextran,RD,Mr4000),wecanvisualizeintercellularcommunicationpathways.Thedye-spreadofLY,indicatingcommunicationviagapjunctions,becomesfirstvisibleinthelate2-cellstage.Fromthe4-cellstageonwardallcellsappeartobewellcoupledbycommunicationchannels,whichallowthefreediffusionofLY.Incontrast,RDremainsrestrictedtotheinjectedcellanditsdescendants.AftertheprimordialgermcellP4hasbeengeneratedinthe24-cellstage,dye-spreadofLYintothiscellanditssomaticsisterDisdelayed.However,therestricteddye-couplingofDisonlytemporary.Afterabriefperioditjoinsthesomaticcompartment.Withthebeginningofthemorphogenesisphasethetwoexistinggermlinecells(thedaughtersofP4)arecompletelyuncoupledfromthesoma,whilethelatterstillformsasingledye-couplingcompartment.Onlyduringthesecondhalfofembryogenesisdifferentseparatesomaticcommunicationcompartmentsareestablished.Wefollowedthepatternofintercellularcommunicationinthealimentarytractandfoundaprogressiverestrictionintosmallerdye-couplingunits.Ourdataarecomparedtothosefoundinothersystemsanddiscussedwithrespecttocellulardeterminationanddifferentiation.