Abstract
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.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Animals
-
Cell Nucleus / metabolism
-
Chromobox Protein Homolog 5
-
Chromosomal Proteins, Non-Histone / genetics
-
Chromosomal Proteins, Non-Histone / metabolism*
-
HeLa Cells
-
Heterogeneous-Nuclear Ribonucleoprotein U / genetics
-
Heterogeneous-Nuclear Ribonucleoprotein U / metabolism*
-
Humans
-
Mass Spectrometry
-
Multiprotein Complexes
-
Protein Binding
-
RNA, Small Interfering / genetics
-
RNA, Small Interfering / metabolism
-
Recombinant Fusion Proteins / genetics
-
Recombinant Fusion Proteins / metabolism
Substances
-
CBX5 protein, human
-
Chromosomal Proteins, Non-Histone
-
Heterogeneous-Nuclear Ribonucleoprotein U
-
Multiprotein Complexes
-
RNA, Small Interfering
-
Recombinant Fusion Proteins
-
Chromobox Protein Homolog 5