Fig. 3.

The nucleotide sequence differences in the μ-OR mRNAs in the B6 and CXBK mouse brains. The μ-opioid receptor mRNAs in the B6 and CXBK mouse brains are illustrated. The rectangles with CR denote the coding regions of the μ-OR mRNAs. Thesolid and broken lines denote the untranslated regions. The nucleotide sequences of the solid line were examined (214 base 5′-UTR and 726 base 3′-UTR). Chromatograms of nucleotide sequences of the regions containing a nucleotide sequence difference are shown. The difference was located at the 202 base upstream site from the translation starting site.Asterisks indicate the nucleotide sequence difference between the B6 and CXBK μ-OR mRNAs.