Physical and functional interaction between heterochromatin protein 1alpha and the RNA-binding protein heterogeneous nuclear ribonucleoprotein U.
By combining biochemical purification and mass spectrometry, we identified proteins associated with human heterochromatin protein 1alpha (HP1alpha) both in the nucleoplasm and in chromatin. Some of these are RNA-binding proteins, and among them is the protein heterogeneous nuclear ribonucleoprotein U (hnRNP U)/SAF-A, which is linked to chromatin organization and transcriptional regulation. Here, we demonstrate that hnRNP U is a bona fide HP1alpha-interacting molecule. More importantly, hnRNP U depletion reduces HP1alpha-dependent gene silencing and disturbs HP1alpha subcellular localization. Thus, our data demonstrate that hnRNP U is involved in HP1alpha function, shedding new light on the mode of action of HP1alpha and on the function of hnRNP U.
Ameyar-Zazoua
Maya
M
CNRS FRE 2944, Institut André Lwoff; Université Paris-Sud, Villejuif F-94801, France.
Souidi
Mouloud
M
CNRS FRE 2944, Institut André Lwoff; Université Paris-Sud, Villejuif F-94801, France.
Fritsch
Lauriane
L
CNRS FRE 2944, Institut André Lwoff; Université Paris-Sud, Villejuif F-94801, France.
Robin
Philippe
P
CNRS FRE 2944, Institut André Lwoff; Université Paris-Sud, Villejuif F-94801, France.
Thomas
Audrey
A
CNRS FRE 2944, Institut André Lwoff; Université Paris-Sud, Villejuif F-94801, France.
Hamiche
Ali
A
CNRS FRE 2944, Institut André Lwoff; Université Paris-Sud, Villejuif F-94801, France.
Percipalle
Piergiorgio
P
Department of Cell and Molecular Biology, Karolinska Institute, S-171 77 Stockholm, Sweden.
Ait-Si-Ali
Slimane
S
CNRS FRE 2944, Institut André Lwoff; Université Paris-Sud, Villejuif F-94801, France.
Harel-Bellan
Annick
A
CNRS FRE 2944, Institut André Lwoff; Université Paris-Sud, Villejuif F-94801, France. Electronic address: ahbellan@vjf.cnrs.fr.
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D034722:Heterogeneous-Nuclear Ribonucleoprotein U / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry; D046912:Multiprotein Complexes; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
C000715594:CBX5 protein, human; D002868:Chromosomal Proteins, Non-Histone; D034722:Heterogeneous-Nuclear Ribonucleoprotein U; D046912:Multiprotein Complexes; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D000090266:Chromobox Protein Homolog 5