HP1: facts, open questions, and speculation.
The demonstration, over a decade ago, that HP1 is a highly conserved constituent of heterochromatin was accompanied by the explicit view that this protein plays a pivotal role in epigenetic regulation (P.B. Singh, J.R. Miller, J. Pearce, R. Kothary, R.D. Burton, R. Paro, T.C. James, and S.J. Gaunt, 1991, Nucleic Acids Res. 19, 789-794). Recent studies have confirmed this view, unveiling specific interactions of HP1 with a variety of histone and nonhistone proteins. We discuss here some of these observations, concentrating on structure-function relationships and intracellular dynamics. Integrating the available information, we also present a hypothetical model describing how HP1, acting as a bifunctional cross-linker, could organize peripheral heterochromatin and contribute in the compartmentalization of the cell nucleus.
Singh
Prim B
PB
Nuclear Reprogramming Laboratory, Division of Gene Expression and Development, The Roslin Institute (Edinburgh), Midlothian, UK. prim.singh@bbsrc.ac.uk
Georgatos
Spyros D
SD
D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry*; D002942:Circular Dichroism; D019281:Dimerization; D029721:Drosophila Proteins / Q000737:chemistry*; D004331:Drosophila melanogaster; D006570:Heterochromatin / Q000737:chemistry; D006657:Histones / Q000737:chemistry; D008958:Models, Molecular; D009685:Nuclear Envelope / Q000378:metabolism; D010455:Peptides / Q000737:chemistry
D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D006570:Heterochromatin; D006657:Histones; D010455:Peptides; C452193:heterochromatin protein 1, Drosophila