EXPRESSION OF TGF-BETA TYPE-II RECEPTOR MESSENGER-RNA IN THE CNS

MEMBERS of the TGF-beta family have been described to bind to a hetero meric complex of two types of serine/threonine kinase receptors, named T beta R-I and T beta R-II. These receptor molecules are essential fo r TGF-beta-specific signalling. Several type I and type II receptors h ave been identified by a variety of methods. TGF-beta 2 and 3 are wide ly expressed in the CNS and exert multiple functions on neurones and g lia. Although the T beta R-I molecule is abundant in the CNS, it was u nclear whether the type II receptor found in peripheral organs is also expressed in the CNS. Previous, negative findings, seemed to suggest that a novel, as yet undescribed type II receptor may be expressed in the CNS. We used competitive RT-PCR to detect T beta R-II mRNA in rats at different stages of development (E18, P6, adult) and in different tissues. We detected this mRNA in the lung, liver, heart, gut, kidney, and pituitary of adult rats. Surprisingly, and in contrast to previou s studies, similar levels of the T beta R-II mRNA were also detected i n several regions of the CNS, namely cortex, midbrain, cerebellum, bra in stem and hippocampus. We therefore tentatively conclude that TGF-be ta 2 and 3 may signal in the brain by means of the same type-I and -II receptors as found in peripheral organs.