Figure 5.

miR-1 shapes the embryonic expression pattern of a ubiquitously transcribed miR-1 sensor mRNA. (A–D) Whole mounts of control noninjected (A,B) or miR-1 MO knockdown (C,D) embryos at 30 hpf, expressing a GFP sensor transgene with three partially complementary targets for miR-1 (3xIPT-miR-1). GFP is expressed from the ubiquitously expressed promoter of the β-actin gene (β-actin-promoter). (A,C) Show fluorescent expression of the GFP protein (green). (B,D) Show expression levels of the GFP-mRNA (blue). The inset shows an enlarged view of the muscle. (C) The GFP sensor protein and mRNA observed in the trunk of noninjected embryos corresponds primarily to nonmuscle tissue (i.e., neural tube, the vasculature, the pronephros, and the skin) and is excluded form muscle. (D) Note that blocking miR-1 function leads to a strong up-regulation of the GFP mRNA levels in muscle.