Northern blot analysis of mRNA expression of mouse SOCS-1, SOCS-5, WSB-2, and ASB-1 in normal adult mouse tissues and in mouse embryos. Northern blot analysis of poly(A)+ mRNA extracted from a range of adult mouse tissues (Left) and mouse embryos and yolk sac (Right) as described (4). Sal. Gland, salivary gland; MLN, mesenteric lymph node; E9–E18, embryos from the 9th through to the 18th day of gestation; P1, 1 day after birth. Size markers in kilobases (kb) are shown to the left of the figure, and the identity of probes is shown to the right.