SRA- and SET-domain-containing proteins link RNA polymerase V occupancy to DNA methylation.

RNA-directed DNA methylation in Arabidopsis thaliana depends on the upstream synthesis of 24-nucleotide small interfering RNAs (siRNAs) by RNA POLYMERASE IV (Pol IV) and downstream synthesis of non-coding transcripts by Pol V. Pol V transcripts are thought to interact with siRNAs which then recruit DOMAINS REARRANGED METHYLTRANSFERASE 2 (DRM2) to methylate DNA. The SU(VAR)3-9 homologues SUVH2 and SUVH9 act in this downstream step but the mechanism of their action is unknown.

Further SAR studies on bicyclic basic merbarone analogues as potent antiproliferative agents.

Pyrimidopyrimidine derivatives 1 were prepared as rigid thioanalogues of merbarone (a catalytic topoisomerase II inhibitor) and screened as antiproliferative agents against different tumor cell lines. A number of the synthesized compounds emerged as cytotoxic in cell-based assays (MT-4, HeLa and MCF-7 cells) at low micromolar concentrations. In a National Cancer Institute screening, selected member of the series showed a broad spectrum of antiproliferative activity against various tumours (melanoma, renal, CNS, colon and breast cancers).

Folding versus charge: understanding selective target recognition by the thrombin aptamers.

The use of nucleic acids as drugs represents a consistently growing approach. Different therapeutical strategies take advantage of the biological and biophysical properties of DNA and RNA to properly modulate activity of selected targets. A peculiar characteristic of these molecules is their structural flexibility which allows them to assume distinct foldings depending upon their sequence and/or environment.