Are transcription (RNA synthesis) or translation (protein synthesis) required for cleavage and/or early development?
Many eggs contain maternal stores of mRNA or proteins used during early development of the zygote. You can ask when zygotic transcription and/or protein synthesis are required by inhibiting these biochemical processes with either Actinomycin (an inhibitor of RNA polymerase) or cycloheximide (a protein synthesis inhibitor), respectively. Procedure: a. Fertilize a fairly large number of eggs. b. Within a few minutes after fertilization, transfer a fraction of the eggs to ASW containing 100 or 500 micrograms/ml actinomycin. Treat another batch of eggs with 100 or 500 micrograms/ml cycloheximide (emetine or puromycin can be substituted for cycloheximide). Remember to keep a parallel untreated culture as a control. c. Monitor cleavage and development of the treated and control embryos until the controls have reached the late gastrula-stage (or longer). You might also try adding actinomycin or cycloheximide during later development. Return to contents…
