Fig. 4

Ybx1 is required for localization and regulated processing of sqt RNA.

(A) Control embryos at 23°C show sqt RNA localization at the 1-cell and 4-cell stage. sqt RNA transport is delayed in 1-cell Mybx1^sa42 embryos at 28.5°C, but localizes correctly by the 4-cell stage. At 23°C, sqt RNA largely remains in the yolk even at 4-cell stage and sqt RNA that reaches the blastoderm is mis-localized. Localization of sqt RNA is restored in Mybx1 by ybx1-2a-gfp MTg, but not by PTg. Localization of wnt8a RNA is normal in Mybx1^sa42 mutants at 28.5°C and 23°C. Scale bar, 100 µm. (B) Q-RT-PCRs to detect total sqt RNA levels show a mild reduction in Mybx1 compared to controls. Error bars show standard deviation from three experiments. (C) RT-PCR to detect sqt in control and Mybx1 mutants at 1-cell, 4-cell and 16-cell stages. Products are indicated on the right, and sizes on the left. Polyadenylated sqt RNA is detected from 16-cells in controls, and at 1-cell in Mybx1 mutants. Splicing of sqt intron 1 and sqt intron 2 occurs earlier in Mybx1 embryos compared to controls. PCR to detect actin is shown as control.