The methylation status of the genes of telomerase reverse transcriptase (tert) and telomerase RNA (terc) was determined in brain tissues of Danio rerio of different age. It is found that, regardless of the age of fish, the regulatory region of the tert gene was completely methylated, whereas the coding region remained unmethylated in all cases. The level of methylation of the region located downstream of the coding region of the terc gene changes with age. This region was analyzed in the samples of other tissues, and its methylation status was also nonuniform. The alteration of the methylation status in the 3'-untranslated region of the terc gene suggests the possibility of transcription of the antisense strand in this region.
