EN
In Southern blot analysis of Paramecium genomic DNA using β-adrenergic specific oligonucleotides labelled with Digoxigenin-ddUTP, the DNA species of the same molecular size were detected by different molecular probes. The 6.5 kb DNA species hybridized with the probes directed to the adjacent β2-receptor transmembrane domains: to TM3 - including Asp 113 involved in β-agonists and antagonists binding, and to TM4 - the oligonucleotide being one of the "gene-specific universal mammalian sequence-tagged site”. Since a profound physiological effect of beta-agonists and antagonists has been previously observed in Paramecium, such a hybridization pattern may suggest an existence of Paramecium DNA sequences homologous to those of metazoan eukaryotes encoding for a membrane beta-adrenergic receptor.