Fig. 5 The S4.2 enhancer is composed of activating and repressive elements. (A) Sequences of the #2/#2* region and derived fragments that were examined for the regulatory activity. PBSI and the 28-bp repressive region are indicated by red letters. (B?G) Stable (B, D?G) or transient (C) GFP expression of the deleted versions of S4.2-EGFP. (H?J, H′?J′) mRNA expression of S4.2Δ2c-EGFP was visualized using WMISH. Arrowheads indicate GFP expression in the MHB. Lateral (B?J) and dorsal (H′?J′) views are shown. d, diencephalon; dos, distal optic stalk; h, hindbrain; m, midbrain; op, olfactory placode; os, optic stalk; ov, otic vesicle, r1/3/5, rhombomere 1/3/5. Scale bars, 200 μm.
Reprinted from Developmental Biology, 316(2), Inoue, F., Parvin, M.S., and Yamasu, K., Transcription of fgf8 is regulated by activating and repressive cis-elements at the midbrain-hindbrain boundary in zebrafish embryos, 471-486, Copyright (2008) with permission from Elsevier. Full text @ Dev. Biol.