Fig. 5. Functional analysis in animal cap explants of clones implicated in post-transcriptional regulation. mRNAs for 13-A10/hnRNP-A/B, 46-B2/snRNP-B, 51-B11/snRNP-D, 54-G3/RNA helicase and 51-D6/RNA-bp EWS were injected into both animal cap cells at the two-cell stage, either alone or together with 15 pg of noggin RNA. RT-PCR analysis was performed at stage 20 (tadpoles). In all instances, the neural tissue induced is anterior in character, and no posterior (spinal cord) neural markers are detected. Similarly, there is no expression of mesodermal derivatives, as judged muscle actin (muscle) and collagen-type II (notochord) expression. Markers used are: NCAM and NRP-1, pan-neural; Otx2 and Pax6, forebrain/midbrain; XAG, cement gland; En2, midbrain/hindbrain boundary; Hoxb9, spinal cord; muscle actin, muscle.