Figure 1.

IκBβ but not IκBα is highly expressed in mouse testes. Multiple tissue Northern blot (A) and ribonuclease protection (B) analyses show that IκBβ mRNA is highly expressed within the testis more than in any other tissue tested. In contrast, IκBα mRNA is barely detectable within the testis. (C) Western blot analysis of total testis extracts shows that this difference in IκBβ and IκBα expression holds up at the protein level. The left panel was probed with an IκBα antibody and the right panel was probed with an IκBβ antibody. (D) Northern blot analysis of a multiple tissue blot shows that high level IκBβ expression does not occur in ovary, suggesting that this expression is not a general phenomenon of reproductive tissues.