Transcription during early embryogenesis ofLeptinotarsa (Coleoptera) : An autoradiographic analysis

RNA synthesis was investigated in precleavage stages (0-5 h after egg deposition) and cleavage stages (5-36 h) ofLeptinotarsa by autoradiography. In precleavage stages the first detectable RNA synthesis occurs after the maturation divisions. Label is found in the female pronucleus during the short period of migration towards the interior of the egg and in the polar body nuclei. In no case was label found in the sperm pronuclei or during the period when the female pronucleus is attached to a male pronucleus prior to fusion (pronuclear prefusion phase). During cleavage, intranuclear labelling can be shown at all developmental stages except the 2-nuclei stage. RNA synthesis increases with age. α-Amanitin completely inhibits the autoradiographically detectable RNA synthesis.