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Regulatory subunits type II (RII) purified from human, pig and bovine brains were compared using 11 monoclonal antibodies (MoAb) against bovine brain RII. Bovine RII has at least 5 antigenic sites located in the N‐terminal 1‐110 residues. Immunochemical difference detected between human and animal RII was more pronounced than between pig and bovine RII. Certain MoAb influenced R‐cAMP binding and holoenzyme formation. RII of the three species responded to MoAb attachment in a similar fashion. The results suggest that anchoring of neural protein kinase via the N‐terminal part of RII may influence the enzyme activity.

The regulatory subunit type II (RII) of cAMP‐dependent protein kinase purified from human brain was represented by two proteins with apparent molecular masses of 51‐52 kD and 54 kD. Dephosphorylation of human RII containing 3 mol phosphate/mol protein did not change the electrophoretic pattern. One‐dimensional peptide mapping of 51‐52 kD and 54 kD proteins after digestion with St. aureus V8 protease evidenced to their being distinct proteins. The data obtained permit to assume that human RII of neural type is represented by two isoforms.

Abstract. The hTERT gene encodes the telomerase catalytic subunit that plays a key role in cancer cell immortalization. Earlier, hTERT amplification was detected in squamous cell cervical carcinomas (SCC), however possible relations between elevated hTERT mRNA level and gene amplification was not studied. Here, we compared the hTERT expression and copy number in the same tumors by quantitative real-time PCR. The hTERT DNA copy number was virtually unchanged in all 33 studied tumors, when compared to normal tissues. This result was confirmed using two reference genes ß-actin and ß-D-glucuronidase. Nevertheless, the activation of hTERT expression was found in 80% of cases (37/46, p<0.001). There was no correlation between the degree of mRNA increase and the tumor size and/or presence of metastases. No hTERT gene expression was observed in 20% of cases (9/46), while the control GADPH expression was unchanged. The detected elevation of the hTERT mRNA level was found using primers specific to functionally active full-length isoform of mRNA. Similar results were obtained with SCC cell lines carrying human papilloma virus (HPV) genomes. We conclude that frequent activation of hTERT expression in SCC is not associated with gene amplification.