Meis Proteins Are Required for Histone H4 Acetylation at Hox-Regulated Promoters

(A) Diagram of hoxb1a and hoxb2a regulation by Hox, Pbx, and Meis factors in zebrafish rhombomere 4 (PG1, paralog group 1).

(B) Dissection of 14 hpf zebrafish embryos (black line indicates position of cut) produces a posterior piece (Post) expressing hoxb1a (black shading) and an anterior piece (Ant) not expressing hoxb1a.

(C) ChIP analysis reveals that Pbx, Meis, and Hoxb1a/b occupy the hoxb1a promoter in posterior (Post), but not anterior (Ant), tissues at 14 hpf.

(D) ChIP analysis of zebrafish embryos reveals that AcH4 is higher in posterior than anterior tissues for the hoxb1a and hoxb2a promoters, but not for the pax2 promoter.

(E) Expression of a Meis dominant-negative construct (PBCAB; right panel) blocks hoxb1a expression (dark blue stain) in zebrafish r4 (compare to control embryo; left panel). Panels show close-ups of the hindbrain with anterior to the top.

(F) ChIP analysis reveals that using a dominant-negative construct (PBCAB) to interfere with Meis function reduces AcH4 at the hoxb1a and hoxb2a promoters, but not at the otx1 promoter, in zebrafish embryos. Data are expressed as the ratio of PBCAB-injected/control-injected embryos.

Error bars indicate standard deviation calculated from a minimum of three experiments.