Heterochromatin protein 1

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Chromobox homolog 1
Chromobox homolog 1
CBX1 dimer (yellow) with EMSY, according to PDB  2FMM

Existing structural data : 2fmm

Properties of human protein
Mass / length primary structure 118 aa; 13.73 kDa
Secondary to quaternary structure Homodimer
Precursor (185 aa; 21.4 kDa)
Isoforms HP1α, HP1β, HP1γ
Identifier
Gene names CBX1  ; CBX; HP1
External IDs
Occurrence
Parent taxon Eukaryotes
Orthologue
human mouse
Entrez 10951
Ensemble ENSG00000108468 ENSMUSG00000018666
UniProt P83916 P83917
Refseq (mRNA) NM_006807 NM_007622
Refseq (protein) NP_006798 NP_031648
Gene locus Chr 17: 43.5 - 43.53 Mb Chr 11: 96.65 - 96.67 Mb
PubMed search 10951

The family of heterochromatin proteins 1 ( HP1 ) (also known as “Chromobox homolog”, CBX) are highly conserved adapter molecules that take on a multitude of essential functions in the cell nucleus. These include epigenetic gene regulation , maintaining genome stability and creating a “platform” for rebuilding cell nuclei in the final phase of mitosis . It was first described in 1986 by Sarah Elgin in Drosophila melanogaster as a protein which, as a mutated form, is associated with the suppression of position effect variegation . In 1991, Prim Singh demonstrated that HP1 is a highly conserved protein of heterochromatin and that it plays a fundamental role in epigenetic regulation .

Isoforms

In mammals there are the isoforms HP1α, HP1β and HP1γ.

HP1β

HP1β interacts directly with the histone methyltransferase Suv (3) 9h1 and is a component of pericentric and telomeric heterochromatin . HP1β can dose-dependently silence genes on pericentric heterochromatin. The process of shutdown is mediated by the interaction of the HP1β chromodomain and the histone modification Me (3) K9H3.

Individual evidence

  1. ↑ James TC, Elgin SC: Identification of a nonhistone chromosomal protein associated with heterochromatin in Drosophila melanogaster and its gene . In: Mol. Cell. Biol . 6, No. 11, November 1986, pp. 3862-72. PMID 3099166 . PMC 367149 (free full text).
  2. ↑ Eissenberg JC, James TC, Foster-Hartnett DM, Hartnett T, Ngan V, Elgin SC: Mutation in a heterochromatin-specific chromosomal protein is associated with suppression of position-effect variegation in Drosophila melanogaster . (PDF) In: Proc. Natl. Acad. Sci. USA . 87, No. 24, December 1990, pp. 9923-7. PMID 2124708 . PMC 55286 (free full text).
  3. ↑ Singh PB, Miller JR, J Pearce, et al. : A sequence motif found in a Drosophila heterochromatin protein is conserved in animals and plants . In: Nucleic Acids Res . 19, No. 4, February 1991, pp. 789-94. PMID 1708124 . PMC 333712 (free full text).
  4. ↑ Aagaard L, Laible G, Selenko P, et al. : Functional mammalian homologues of the Drosophila PEV-modifier Su (var) 3-9 encode centromere-associated proteins which complex with the heterochromatin component M31 . In: EMBO J. . 18, No. 7, April 1999, pp. 1923-38. doi : 10.1093 / emboj / July 18, 1923 . PMID 10202156 . PMC 1171278 (free full text).
  5. ↑ Wreggett KA, Hill F, James PS, Hutchings A, Butcher GW, Singh PB: A mammalian homologue of Drosophila heterochromatin protein 1 (HP1) is a component of constitutive heterochromatin . In: Cytogenet. Cell Genet. . 66, No. 2, 1994, pp. 99-103. PMID 8287692 .
  6. ↑ Sharma GG, Hwang KK, Pandita RK, et al. : Human heterochromatin protein 1 isoforms HP1 (Hsalpha) and HP1 (Hsbeta) interfere with hTERT-telomere interactions and correlate with changes in cell growth and response to ionizing radiation . In: Mol. Cell. Biol . 23, No. 22, November 2003, pp. 8363-76. PMID 14585993 . PMC 262350 (free full text).
  7. ↑ hard stone R, Sharghi-Namini S, M Fox, et al. : Heterochromatin protein 1 modifies mammalian PEV in a dose- and chromosomal-context-dependent manner . In: Nat. Genet. . 23, No. 4, December 1999, pp. 457-61. doi : 10.1038 / 70579 . PMID 10581035 .

literature

  • Singh PB, Georgatos SD: HP1: facts, open questions, and speculation . In: J. Struct. Biol . 140, No. 1-3, 2002, pp. 10-6. PMID 12490149 .

Web links