Chromosome termini of the monocot plant Othocallis siberica are maintained by telomerase, which specifically synthesises vertebrate-type telomere sequences.

摘要: Lack of Arabidopsis-type T 3 AG telomere sequences has recently been reported for the majority investigated taxa monocot order Asparagales. In to investigate this phenomenon in more detail, we conducted extensive cytogenetic and molecular analyses telomeres Othocallis siberica, a member order. Terminal restriction fragment analysis together with BaI31 exonuclease assay showed that chromosome termini O. siberica are formed by long stretches (more than 10 kbp) vertebrate-type 2 repeats. addition, telomerase activity specifically synthesising (T ) n sequence was detected protein extracts repeat amplification protocol (TRAP). Fluorescence situ hybridisation (FISH) revealed presence at all few additional regions 0. chromosomes, whereas DNA peptide nucleic acid (PNA) probes did not hybridise chromosomes Othocallis, except polymorphic blocks (interstitial) 4 (terminal). These interstitial/terminal apparently composed large represent unique example interspersion two types telomeric repeats within one genome. This may be reflection recent evolutionary switch from Arabidopsis- plant group.