Chicken MAR binding protein p120 is identical to human heterogeneous nuclear ribonucleoprotein (hnRNP) U.
We have previously identified two proteins from chicken oviduct nuclei that specifically bind to matrix/scaffold attachment regions (MARs/SARs). Here one of these proteins, named p120 due to its apparent molecular weight, is purified to near homogeneity and shown to be identical to a previously described component of heterogeneous nuclear ribonucleoprotein particles, hnRNP U, on the basis of amino acid sequence analysis of tryptic peptides. p120 binds to multiple MAR fragments provided they have a minimal length of approximately 700 bp. Binding of MAR fragments is specifically competed by homoribopolymers poly(G) and poly(I), which form four-stranded structures. Our results suggest that p120/hnRNP U may serve a dual function, first as a component of hnRNP particles, and second as an element in the higher-order organization of chromatin.
von Kries
J P
JP
Institut für Physiologische Chemie, Universitäts-Krankenhaus Eppendorf, Hamburg, Germany.
Buck
F
F
Strätling
W H
WH
D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D034722:Heterogeneous-Nuclear Ribonucleoprotein U; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D008969:Molecular Sequence Data; D015183:Restriction Mapping; D012261:Ribonucleoproteins / Q000302:isolation & purification / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D034722:Heterogeneous-Nuclear Ribonucleoprotein U; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D012261:Ribonucleoproteins