[Properties of satellite DNA of three plant species of the subtribe Citrinae].

The properties of stDNA of three species of the subtribe Citrinae have been investigated. The buoyant density of the main component is 1.693 g/cm3, that of satellite component is 1.712 g/cm3 and 1.715 g/cm3. The differential melting curves of satellite components reveal two melting zones. Some of stDNAs are melted within a broad temperature range, while others--at higher temperatures as a narrow peak. The reassociation kinetics suggest that 50-54% of stDNA are a fast reassociating fraction with the length of repeating sequences of 0.8-1.1 x 10(2) base pairs. Based on the values of Tm and buoyant density the 5-methylcytosine content in stDNA was calculated and was found equal to 20-35%. Using equilibrium ultracentrifugation in the actinomycin D--CsCl density gradient the stDNAs of the subtribe Citrinae were separated into constituent components.