The content of casein kinase 2 is considerably decreased in ribosome‐free extracts of the frontal cortex of schizophrenic and Alzheimer's disease patients in comparison to normal brains as has been demonstrated by means of immunoblotting. The activity of casein kinase 2 towards endogenous substrates and casein is also diminished in the cases of mental pathologies examined. This phenomenon may explain the well‐known aberrations in the phosphorylation of structural proteins of human brain which are intrinsic for the mental diseases.

Inbred mice expressing endogenous mouse mammary tumor virus envelope proteins can be infected with exogenous virus, and the mammary tumors that develop in these mice usually have many proviruses integrated in their genomes, indicating that this virus is not subject to receptor interference. We show here that transgenic mice expressing an exogenous mouse mammary tumor virus (C3H) envelope protein can still be infected with this virus. Moreover, cultured mammary gland cells expressing the mouse mammary tumor virus (C3H) envelope protein can be superinfected with pseudotyped viruses bearing that same protein. Thus cellular expression of the mouse mammary tumor virus envelope protein does not block superinfection in vivo or in vitro.

2-Oxoglutarate (2-OG) is a metabolic precursor of glutamate and may be utilized to replenish the neurotransmitter pool. 2-OG is rapidly transported into neurons by a high-affinity carrier that is particularly prevalent in gluta-matergic terminals. Here we report the kinetics of [U-¹⁴C]2-OG uptake by crude synaptosomal preparations from bovine and rat retina and brain, and the modulatory effects of glutamate and glutamine. In all four tissues, 2-OG uptake was mediated by a high-affinity system (K_t ≈ 1 µM) that was subject to negative feedback control by glutamate and biphasic modulation by glutamine (another precursor of neurotransmitter glutamate).

It is demonstrated by filter‐binding assay that casein kinase 2 from Rana temporaria oocytes binds rRNA in vitro with high affinity. Ligand‐blotting shows that rRNA‐binding activity is inherent to α and α′ subunits of the enzyme. Increase of pH from 6.5 to 7.5 has little effect on casein kinase but completely suppresses rRNA‐binding activity of the enzyme. Sedimentation coefficient of casein kinase 2 also defends on pH: at pH 7.5 it is mainly 10 S, and at 6.5 – 18 S. At pH 6.95 the amounts of both forms are equal. The heavy form of casein kinase 2 practically lacks rRNA‐binding activity. Casein kinase 2; RNA‐binding; pH

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