Table 1.

Phenotypic effects resulting from Xvax1 microinjection in Xenopus embryos

RNA injected (pg)	In situ probe used	Stage analyzed	Strong reduction (%)	Weak reduction (%)	Normal expression (%)	No. of embryos analyzed
Xvax1 500	Rx	N	26	40	34	42
100		T	1	9	90	85
250		T	0	14	86	52
500		T	(19)	34	47	119
500	Xpax2	N	7	43	50	30
500		T	(16)	31	54	70
500	Xpax6	N	5	48	47	42
500		T	(16)	34	50	95
1acZ					100	57
500

Embryos were injected at the two-cell stage in both blastomeres, collected at neurula (N) or tailbud (T) stages and probed with Xrx, Xpax2, or Xpax6, as indicated. Data represent the results of at least three independent experiments. lacZ injections alone served as a control and did not result in any obvious phenotypic alterations. Neurula and tailbud stage embryos were counted as a strong reduction when they show no expression or at least an 80% reduction in marker gene expression in the eye field or in the eye cup. A 25%–80% was considered as a weak reduction. Because the injection of high doses (500 pg) of Xvax1 inhibits head development, the anterior expression of all markers is lost at tadpole stages, as indicated by parentheses.