Fig. 3. Expression of Cx39 mRNA in different mouse tissues detected by northern blot hybridization. (A,B) Similar amounts of total RNA were applied as demonstrated after staining of the 18S rRNA with ethidium bromide. (A) Expression of mCx39 mRNA during different developmental stages (ED13.5 to P0) of the embryo but not in yolk sac, placenta or in utero. (B) In the eye and chest (including intercostal muscle) of neonatal (P0) and two-day-old mice (P2) as well as in the P2 heads after removing the brain, Cx39 mRNA was expressed at low levels.