Fig. 9. Repression of chicken Hoxb9 expression by overexpression of mouse Ring1B and Mel18. (A, part a) In ovo electroporation. A pair of electrodes held by a manipulator is inserted through a window and placed over the vitelline membrane overlying the embryo. Plasmid solution colored by Nile Blue is injected into the developing spinal cord as indicated by a yellow bracket. (parts b,c) Hoxb9 expression in seven-somite (part b) and 15-somite (part c) stage embryos. Somite boundaries are shown. (B, part a) Expression of mRing1B 24 hours after electroporation. (parts b-d) Repression of Hoxb9 expression observed 48 hours after electroporation. The anterior boundaries of Hoxb9 expression in the control sides are indicated by arrows. Downregulation of Hoxb9 expression by exogenous Ring1B are indicated by brackets. (C, part a) Expression of mMel18 24 hours after electroporation. (part b) Repression of cHoxb9 expression 48 hours after electroporation. The anterior boundary of Hoxb9 expression in the control side is indicated by an arrow. Downregulation of Hoxb9 expression by mouse Mel18 is indicated by a bracket. (D) Ring1B- and Mel18-dependent repression of Hoxb9 expression is influenced by the developmental stage. Frequency of affected embryos by transfection of mouse Ring1B, Mel18 and empty vectors were represented by closed, shaded and open bars, respectively. Mel18-dependent repression is less efficient than that of Ring1B and is similarly influenced by developmental stage. (E) Ring1B-dependent repression of Hoxb9 expression becomes obvious at least 36 hours after the electroporation. Asterisks in D and E indicate results from the identical series of experiments.

Return to article