[Transcriptional regulation macronuclear protein-coding genes in stichotrichous ciliates]

The concept of transcriptional regulation and base promoter structure of genes in eukaryotic organisms rests on two approaches--the experimental (using different methods of directional mutagenesis) and the comparative molecular (comparison of nucleotide sequences in promoter regions of different genes). Investigation of ciliates has led researchers to the conclusion that the protein-coding genes of these organisms lack the classical eukaryotic regulatory elements in the promoter region. This conclusion is based mainly on the usage of the comparative approach, while experimental investigations of such genes are practically absent so far. In the present paper, the comparative molecular analysis of the promoter regions of genes and analysis of the functional role of tubulin, cathepsin and Hsp 70 5'-uncoding areas was performed using new experimental data obtained during investigation of Stylonychia lemnae alpha-tubulin gene. We suggest a new classification of mechanism of transcriptional regulation of protein-coding genes in stichotrichous ciliates.