PvuII Restriction Enzyme Digests of 5'RACE Clones From Pre-MBT Embryos. 5' RACE was performed using total RNA extracted from pre-midblastula transition embryos as described in methods. DNA extracted from individual clones was digested with PvuII. A previously identified 5' RACE clone from 10 days old larvae was also digested as a control. Phage λ DNA digested with HindIII was used as a size marker. The digests were subjected to electrophoresis through a 1.5% agarose gel, stained with ethidium bromide, and photographed under UV light using a digital camera.