DNA topoisomerase IIβ as a molecular switch in neural differentiation of mesenchymal stem cells.

Two isoforms of DNA topoisomerase II (topo II) have been identified in mammalian cells, named topo IIα and topo IIβ. Topo IIα plays an essential role in segregation of daughter chromosomes and thus for cell proliferation in mammalian cells. Unlike its isozyme topo IIα, topo IIβ is greatly expressed upon terminal differentiation of neuronal cells.

Selective silencing of DNA topoisomerase IIβ in human mesenchymal stem cells by siRNAs (small interfering RNAs).

hMSCs (human mesenchymal stem cells) express two isoforms of DNA topo II (topoisomerase II). Although both isoforms have the same catalytic activity, they are specialized for different functions in the cell: while topo IIα is essential for chromosome segregation in mitotic cells, topo IIβ is involved in more specific cellular functions. A number of inhibitors are available that inhibit the catalytic activity of both topo II isoforms.