Fig. 3.

The J element possesses class I OSN-specific enhancer activity. a Transgenes of J13k-gVenus and J-gVenus. The number of Venus-positive independent founders and lines among the total analyzed is shown on the right. Olfr544p, promoter region of Olfr544; gV, membrane-targeted Venus reporter (gapVenus); pA, polyadenylation sequence. b Whole-mount fluorescent images of the MOE and the dorsal OB of hemizygous J13k-gVenus Tg mice and J-gVenus Tg mice. The scale bar is 500 μm. c Confocal images of two-color ISH of Venus (green) with mixed probes of α=−class I OR genes, β=class I OR genes, class I OR genes, and class II OR genes (magenta) in a J-gVenus Tg mice. Enhancer activity of the J element (Venus) was observed in class I OR-positive cells (arrowheads). The scale bar is 20 μm. d Bar graphs showing the percentage of Venus-positive cells that are labeled with the class I or class II OR mixed probes (3112 cells for class I, 3252 cells for class II probes from 3 mice). Co-expression preferentially occurred in class I OR-expressing OSNs. Fisher’s exact test; p < 2.2 × 10⁻¹⁶, ***p < 0.001