The expression of embryonic primary mesenchyme genes of the sea urchin, Strongylocentrotus purpuratus, in the adult skeletogenic tissues of this and other species of echinoderms☆

摘要

Adulttissuesoftheseaurchin,Strongylocentrotuspurpuratus,wereanalyzedfortheproductsofasetofgeneswhoseexpression,intheembryo,isrestrictedtotheskeletogenicprimarymesenchyme(PM).ThreeembryonicPM-specificmRNAswerefoundtobeabundantinadultskeletaltissues(testandlantern),butnotinavarietyofsofttissues.HomologousmRNAswerealsofoundinskeletaltissuesofthecongenericseaurchin,S.droebachiensis,aswellasamoredistantlyrelatedechinoid,Dendrasterexcentricus,andanasteroid,Evasteriastroschellii.ThedistributionsoftwooftheseRNAswereanalyzedinregeneratingspinesofadultS.purpuratususinginsituhybridization.Thesegeneproductswerelocalizedprimarilyinthecalcoblaststhataccumulatedattheregenerationsite.InnonregeneratingspinesSpLM18RNAs,themostabundantofthesegeneproducts,werelocalizedinasmallpopulationofnoncalcoblastcellsscatteredthroughthespineshaft,andwereabsentfromcalcoblasts.Theseobservationssuggestthataprogramofgeneexpressionassociatedwiththeprocessofcalcificationisconservedbothdevelopmentallythroughtheperiodofmetamorphosisandevolutionarilyamongtheechinoderms.