Supplementary Material for: Two faces of Solanaceae telomeres: a comparison between <i>Nicotiana</i> and <i>Cestrum</i> telomeres and telomere-binding proteins

2009-01-30T00:00:00Z (GMT) by Peška V. Sýkorová E. Fajkus J.
While most Solanaceae genera (e.g.<i>Solanum, Nicotiana</i>) possess <i>Arabidopsis</i>-type telomeres of (TTTAGGG)n maintained by telomerase, the genera <i>Cestrum, Vestia</i> and <i>Sessea</i> (<i>Cestrum </i>group) lack these telomeres. Here we show that in the <i>Cestrum</i>-group the activity of telomerase has been lost. Nevertheless, proteins binding the single-stranded G-rich strand of the <i>Arabidopsis</i>-type and related human-type (TTAGGG)n telomeric sequences are present in nuclear extracts of both <i>Nicotiana</i> and <i>Cestrum </i>species. These proteins may have a role in telomere function or other cellular activities. In addition to characterizing DNA binding specificity and molecular weights of these proteins, we searched in both <i>N. tabacum </i>(tobacco) and <i>C. parqui </i>for the presence of POT1-like proteins, involved in telomere capping and telomerase regulation. Analysis of POT1-like proteins available on public databases and cloned by us from <i>C. parqui, </i>revealed the N-terminal OB folds typical for this protein family and a novel, plant-specific conserved C-terminal OB-fold domain (CTOB). We propose that CTOB is involved in protein-protein interactions.

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