Telomerase Genes in Solanaceae

Telomerase is a ribonucleoprotein enzyme complex compensating for replicative shortening of chromosome ends - telomeres.  Its catalytic protein subunit, telomerase reverse transcriptase (TERT), synthetises short oligonucleotide repeats of the consensus sequence (T)nA(G)m, based on the template region sequence of telomerase RNA subunit, TR.  In genomes of higher eukaryotes, including the most common model plant A. thaliana, a paleotetraploid species, a parallel existence of two or more variants of the TERT gene has not been described, suggesting that some unknown restrictions control the copy number of this particular gene per genome. Solanaceae family played important role in telomere and telomerase research, including the first description of telomerase activity in plant cells (Fajkus et al., FEBS Lett. 1996). Moreover, this family involves species with common plant-type telomeres, as well as species lacking these telomeres and corresponding telomerase activity. Intriguingly, three TERT gene variants were described recently in the allopolyploid species of tobacco (N. tabacum). Two of the three sequence variants present in the tobacco genome revealed similarity to two sequence variants found in N. sylvestris and another variant was similar to TERT of N. tomentosiformis (Sykorova et al, Chromosome Res. 2012). We further analyse other Solanaceae species, including hybrids and their progenitors, to trace evolution of TERT genes and possible functional diversity of parental TERT variants in hybrids or polyploids. We will present our latest results in the field of telomerase evolution in Solanaceae.  The research was supported by GACR (projects 13-06943S and 13-10948P) and by CEITEC (CZ.1.05/1.1.00/02.0068, CZ.1.07/2.3.00/20.0043).