a, b, Top, Northern blot analysis of Cx47 expression in adult mouse tissues (a) and eight stages of mouse brain development (b) are shown. Bottom, Equal amounts of total RNA were loaded as demonstrated by staining of 18 S ribosomal RNA with ethidium bromide (bottom). The size of the bands is indicated in kilobases on the right.P0, Postnatal day 0; dpc, dies postcoitum.