Fig. 5.

Regulatory level of pak4 function. Flat mounts of in situ hybridization for ETS class transcription factors fli1a (column A) and fli1b (column B), etsrp1 (column C) and ets1 (column D), and the VEGF receptor flk1 (column E) reveal different dependence on pak4. Expression of the ETS transcription factors was not inhibited at any stage tested, however, expression of fli1b was transiently elevated at in the posterior domain, and etsrp1 in the rostral domain at the 5-somite stage (B and C; red arrowheads). flk1 Expression was reduced in both the anterior and posterior hematopoietic domains (E; red arrowheads). Frequency data are tabulated in (F).