Loss during development of the ability of chick embryonic lens cells to elongate in culture: Inverse relationship between cell division and elongation

摘要

Previousstudieshaveshownthatembryoniclensepithelialcellsofseveralspeciesofvertebrateselongateinculture,asdolenscellswhentheyformfibersinvivo.Otherstudieshaveshownthatmaturelensepithelialcellsdivideratherthanelongateinculture.Todetermineifandwhenduringdevelopmentlensepithelialcellschangeintheirabilitytoelongateinculture,thecentralregionsofembryonicchicklensepitheliawereexplantedatprogressivelylaterstagesofdevelopmentandexaminedhistologicallyafter3daysofcultivation.Cellsfrom6-,9-,12-,and15-day-oldembryoselongatedinculture.Theamountsofthymidine-CH3?—?3Handofadenosine-2-3HincorporatedintoDNA,thepercentageofnucleilabeledwiththymidine-CH3?—?3Handthepercentageofcellswithmitoticfiguresdecreasedaftercultureofexplantsfrom6-day-oldembryos.Bycontrast,epithelialcellstakenfrom19-day-oldembryosdidnotelongateinculture,andshowedanincreaseaftercultureintheamountsofthymidine-CH3?—?3Handofadenosine-2-3HincorporatedintoDNA,inthepercentageofnucleilabeledwiththymidine-CH3?—?3Handinthepercentageofcellswithmitoticfigures.Thus,theabilityoflensepithelialcellstoelongateincultureislostbetweenday15andday19ofdevelopmentofthechickembryo.