Figure 1.

Inhibition of CaM kinase II α subunit mRNA translation resulted in decreased α CaM kinase II activity and subunit protein expression. Hippocampal neurons in culture were exposed to missense (scrambled antisense) or antisense oligonucleotides complementary to the mRNA to the α subunit of CaM kinase II for 3 days. Cultures were then harvested, homogenized, and resolved on SDS/PAGE (see Materials and Methods). (A) Representative Western analysis with a mAb directed against the α subunit shows a high level of expression under missense (control) treatment. Exposure to antisense oligonucleotides resulted in a significant decrease in CaM kinase α subunit expression. (B) Densitometry quantification of CaM kinase II α subunit expression. Western blots were digitized and compared with a standard CaM kinase II expression curve (see Materials and Methods). Western analysis showed that treatment with antisense oligonucleotides resulted in a significant decrease in subunit protein expression. Antisense oligonucleotide exposure for 3 days resulted in a 53.4 ± 6.0% inhibition in CaM kinase II α subunit expression when compared with missense-treated control cultures. (C) Inhibition of CaM kinase II α subunit expression resulted in decreased substrate phosphorylation. CaM kinase II-dependent phosphorylation of exogenously added Syntide II was significantly reduced (35.4 ± 12.3% compared with a missense control) after treatment with antisense oligonucleotide when compared with missense-treated control. **, P < 0.001, Student's t test, n = 4.