A functional connection between the Microprocessor and a variant NEXT complex.

In mammalian cells, primary miRNAs are cleaved at their hairpin structures by the Microprocessor complex, whose core is composed of DROSHA and DGCR8. Here, we show that 5' flanking regions, resulting from Microprocessor cleavage, are targeted by the RNA exosome in mouse embryonic stem cells (mESCs). This is facilitated by a physical link between DGCR8 and the nuclear exosome targeting (NEXT) component ZCCHC8.

Abortive activity of Topoisomerase I: a challenge for genome integrity?

Single-strand breaks (SSB) are discontinuities in one strand of the DNA double helix and are the most common type of damages that arise in cells. SSBs arise mainly from direct attack by intracellular metabolites, however, also essential nuclear processes generate SSBs as intermediates. During the catalytic cycle of DNA topoisomerase I (Top1) a SSB is generated, which is normally transient and rapidly resealed by the enzyme.

Minimal Resection Takes Place during Break-Induced Replication Repair of Collapsed Replication Forks and Is Controlled by Strand Invasion.

A natural and frequently occurring replication problem is generated by the action of topoisomerase I (Top1). Trapping of Top1 in a cleavage complex on the DNA generates a protein-linked DNA nick (PDN), which upon DNA replication can be transformed into a one-ended double-strand break (DSB). Break-induced replication (BIR) has been recognized as a critical repair mechanism of one-ended DSBs.

Using the Flp Recombinase to Induce Site-Specific Protein-DNA Nicks.

A natural and frequent occurring replication insult is generated by the action of DNA Topoisomerase I (Top1). When Top1 gets trapped in a cleavage complex on the DNA, a protein-linked DNA nick (PDN) is generated. Today it is known that PDNs are generated at a high incidence in the cell.

Dexamethasone inhibits IL-9 production by human T cells.

Background: Interleukin 9 (IL-9) is produced by activated CD4+ T cells. Its effects include stimulation of mucus production, enhanced mast cell proliferation, enhanced eosinophil function, and IgE production. These effects are consistent with a role in allergic diseases.