Fig. 8

Overexpression of Mypt1-202 in zebrafish embryos results in constitutive dephosphorylation of Mlc2. Lateral views of representative 48 hpf zebrafish embryos injected with (A) 200 pg myc-long-mypt1 mRNA or (C) 100 pg myc-ppp1r12a-tv202 mRNA. Embryos at bud stage stained with hgg1 (to mark the prechordal plate), shh (midline), pax2.1 (midbrain-hindbrain boundary) and dlx3 (neural plate) after injection of (B) 200 pg myc-long-mypt1 mRNA or (D) 100 pg myc-ppp1r12a-tv202 mRNA. A representative field of presomitic and notochordal mesoderm at the bud stage in control embryos (E), embryos injected with 200 pg myc-long-mypt1 mRNA (F) or 100 pg ppp1r12a-tv202 mRNA (G). (H) The actomyosin driven elongation of mesodermal cells was determined by calculating the length width ratio (y-axis). The crossed bars indicate cells with the long axis length and the short axis width. Error bars are standard error and a * indicates a statistically significant difference from control. All calculations were made on 75 cells from 3 to 5 separate embryos. Statistical significance was calculated using a one-factor ANOVA with Tukey post hoc analysis and is defined as p < 0.05. (I) Embryo lysates from 25 control embryos or 25 embryos injected with either myc-long-mypt1 mRNA or myc-ppp1r12a-tv202 mRNA were analyzed by Western blot using anti-myc, anti-phospho-Mlc2 or anti-Mlc2 antibodies. This biochemical analysis was performed four times.