|Purification and characterization of a nuclear DNA-binding factor complex containing topoisomerase II and chromosome scaffold protein 2.
|Year of Publication
|Ma X, Saitoh N, Curtis PJ
|J Biol Chem
|1993 Mar 25
|Animals, Base Sequence, Cell Differentiation, Cell Line, DNA, DNA Topoisomerases, Type II, DNA-Binding Proteins, Humans, Mice, Molecular Sequence Data, Nuclear Proteins
In a search for factors that influence the process of erythroid differentiation at the molecular level, we have identified UB2, a nuclear protein factor that was originally observed for its ability to bind to a very specific and highly conserved sequence motif present in human, mouse, rabbit, and chicken beta-globin genes, as well as carbonic anhydrase I, c-myb, and the immunoglobulin heavy chain enhancer region. It was also observed for its appearance in undifferentiated but not differentiated mouse erythroleukemia cells. Purification of UB2 by DEAE-cellulose chromatography and repeated passages through a DNA affinity column, revealed a complex pattern with three major components of 170, 116, and 48 kDa, respectively. The 170-kDa protein was identified as topoisomerase (topo) II by Western blot analysis, catalytic assays, and antibody interference with UB2 binding. The complex topo II in UB2, however, has a more stringent sequence requirement for DNA binding than does topo II. The 116-kDa protein has been determined to be a proteolytic product of topo II. The chromosome scaffold protein 2 (135 kDa) copurified with UB2, and anti-scaffold protein 2 serum inhibited UB2 binding to DNA.
|J Biol Chem
|GM30985 / GM / NIGMS NIH HHS / United States
Submitted by mam2155 on March 24, 2014 - 4:16pm