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. 1997 Apr;17(4):2326–2335. doi: 10.1128/mcb.17.4.2326

Identification and characterization of interactions between the vertebrate polycomb-group protein BMI1 and human homologs of polyhomeotic.

M J Gunster 1, D P Satijn 1, K M Hamer 1, J L den Blaauwen 1, D de Bruijn 1, M J Alkema 1, M van Lohuizen 1, R van Driel 1, A P Otte 1
PMCID: PMC232081  PMID: 9121482

Abstract

In Drosophila melanogaster, the Polycomb-group (PcG) genes have been identified as repressors of gene expression. They are part of a cellular memory system that is responsible for the stable transmission of gene activity to progeny cells. PcG proteins form a large multimeric, chromatin-associated protein complex, but the identity of its components is largely unknown. Here, we identify two human proteins, HPH1 and HPH2, that are associated with the vertebrate PcG protein BMI1. HPH1 and HPH2 coimmunoprecipitate and cofractionate with each other and with BMI1. They also colocalize with BMI1 in interphase nuclei of U-2 OS human osteosarcoma and SW480 human colorectal adenocarcinoma cells. HPH1 and HPH2 have little sequence homology with each other, except in two highly conserved domains, designated homology domains I and II. They share these homology domains I and II with the Drosophila PcG protein Polyhomeotic (Ph), and we, therefore, have named the novel proteins HPH1 and HPH2. HPH1, HPH2, and BMI1 show distinct, although overlapping expression patterns in different tissues and cell lines. Two-hybrid analysis shows that homology domain II of HPH1 interacts with both homology domains I and II of HPH2. In contrast, homology domain I of HPH1 interacts only with homology domain II of HPH2, but not with homology domain I of HPH2. Furthermore, BMI1 does not interact with the individual homology domains. Instead, both intact homology domains I and II need to be present for interactions with BMI1. These data demonstrate the involvement of homology domains I and II in protein-protein interactions and indicate that HPH1 and HPH2 are able to heterodimerize.

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Selected References

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  1. Akasaka T., Kanno M., Balling R., Mieza M. A., Taniguchi M., Koseki H. A role for mel-18, a Polycomb group-related vertebrate gene, during theanteroposterior specification of the axial skeleton. Development. 1996 May;122(5):1513–1522. doi: 10.1242/dev.122.5.1513. [DOI] [PubMed] [Google Scholar]
  2. Alkema M. J., Bronk M., Verhoeven E., Otte A., van 't Veer L. J., Berns A., van Lohuizen M. Identification of Bmi1-interacting proteins as constituents of a multimeric mammalian polycomb complex. Genes Dev. 1997 Jan 15;11(2):226–240. doi: 10.1101/gad.11.2.226. [DOI] [PubMed] [Google Scholar]
  3. Alkema M. J., Wiegant J., Raap A. K., Berns A., van Lohuizen M. Characterization and chromosomal localization of the human proto-oncogene BMI-1. Hum Mol Genet. 1993 Oct;2(10):1597–1603. doi: 10.1093/hmg/2.10.1597. [DOI] [PubMed] [Google Scholar]
  4. Alkema M. J., van der Lugt N. M., Bobeldijk R. C., Berns A., van Lohuizen M. Transformation of axial skeleton due to overexpression of bmi-1 in transgenic mice. Nature. 1995 Apr 20;374(6524):724–727. doi: 10.1038/374724a0. [DOI] [PubMed] [Google Scholar]
  5. Bornemann D., Miller E., Simon J. The Drosophila Polycomb group gene Sex comb on midleg (Scm) encodes a zinc finger protein with similarity to polyhomeotic protein. Development. 1996 May;122(5):1621–1630. doi: 10.1242/dev.122.5.1621. [DOI] [PubMed] [Google Scholar]
  6. Brunk B. P., Martin E. C., Adler P. N. Drosophila genes Posterior Sex Combs and Suppressor two of zeste encode proteins with homology to the murine bmi-1 oncogene. Nature. 1991 Sep 26;353(6342):351–353. doi: 10.1038/353351a0. [DOI] [PubMed] [Google Scholar]
  7. Chien C. T., Bartel P. L., Sternglanz R., Fields S. The two-hybrid system: a method to identify and clone genes for proteins that interact with a protein of interest. Proc Natl Acad Sci U S A. 1991 Nov 1;88(21):9578–9582. doi: 10.1073/pnas.88.21.9578. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Cohen K. J., Hanna J. S., Prescott J. E., Dang C. V. Transformation by the Bmi-1 oncoprotein correlates with its subnuclear localization but not its transcriptional suppression activity. Mol Cell Biol. 1996 Oct;16(10):5527–5535. doi: 10.1128/mcb.16.10.5527. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. DeCamillis M., Cheng N. S., Pierre D., Brock H. W. The polyhomeotic gene of Drosophila encodes a chromatin protein that shares polytene chromosome-binding sites with Polycomb. Genes Dev. 1992 Feb;6(2):223–232. doi: 10.1101/gad.6.2.223. [DOI] [PubMed] [Google Scholar]
  10. Deatrick J., Daly M., Randsholt N. B., Brock H. W. The complex genetic locus polyhomeotic in Drosophila melanogaster potentially encodes two homologous zinc-finger proteins. Gene. 1991 Sep 15;105(2):185–195. doi: 10.1016/0378-1119(91)90150-a. [DOI] [PubMed] [Google Scholar]
  11. Durfee T., Becherer K., Chen P. L., Yeh S. H., Yang Y., Kilburn A. E., Lee W. H., Elledge S. J. The retinoblastoma protein associates with the protein phosphatase type 1 catalytic subunit. Genes Dev. 1993 Apr;7(4):555–569. doi: 10.1101/gad.7.4.555. [DOI] [PubMed] [Google Scholar]
  12. Fields S., Song O. A novel genetic system to detect protein-protein interactions. Nature. 1989 Jul 20;340(6230):245–246. doi: 10.1038/340245a0. [DOI] [PubMed] [Google Scholar]
  13. Franke A., DeCamillis M., Zink D., Cheng N., Brock H. W., Paro R. Polycomb and polyhomeotic are constituents of a multimeric protein complex in chromatin of Drosophila melanogaster. EMBO J. 1992 Aug;11(8):2941–2950. doi: 10.1002/j.1460-2075.1992.tb05364.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Harper J. W., Adami G. R., Wei N., Keyomarsi K., Elledge S. J. The p21 Cdk-interacting protein Cip1 is a potent inhibitor of G1 cyclin-dependent kinases. Cell. 1993 Nov 19;75(4):805–816. doi: 10.1016/0092-8674(93)90499-g. [DOI] [PubMed] [Google Scholar]
  15. Kennison J. A. The Polycomb and trithorax group proteins of Drosophila: trans-regulators of homeotic gene function. Annu Rev Genet. 1995;29:289–303. doi: 10.1146/annurev.ge.29.120195.001445. [DOI] [PubMed] [Google Scholar]
  16. Kingston R. E., Bunker C. A., Imbalzano A. N. Repression and activation by multiprotein complexes that alter chromatin structure. Genes Dev. 1996 Apr 15;10(8):905–920. doi: 10.1101/gad.10.8.905. [DOI] [PubMed] [Google Scholar]
  17. Lonie A., D'Andrea R., Paro R., Saint R. Molecular characterisation of the Polycomblike gene of Drosophila melanogaster, a trans-acting negative regulator of homeotic gene expression. Development. 1994 Sep;120(9):2629–2636. doi: 10.1242/dev.120.9.2629. [DOI] [PubMed] [Google Scholar]
  18. Müller J., Gaunt S., Lawrence P. A. Function of the Polycomb protein is conserved in mice and flies. Development. 1995 Sep;121(9):2847–2852. doi: 10.1242/dev.121.9.2847. [DOI] [PubMed] [Google Scholar]
  19. Nomura M., Takihara Y., Shimada K. Isolation and characterization of retinoic acid-inducible cDNA clones in F9 cells: one of the early inducible clones encodes a novel protein sharing several highly homologous regions with a Drosophila polyhomeotic protein. Differentiation. 1994 Jun;57(1):39–50. doi: 10.1046/j.1432-0436.1994.5710039.x. [DOI] [PubMed] [Google Scholar]
  20. Orlando V., Paro R. Mapping Polycomb-repressed domains in the bithorax complex using in vivo formaldehyde cross-linked chromatin. Cell. 1993 Dec 17;75(6):1187–1198. doi: 10.1016/0092-8674(93)90328-n. [DOI] [PubMed] [Google Scholar]
  21. Paro R., Hogness D. S. The Polycomb protein shares a homologous domain with a heterochromatin-associated protein of Drosophila. Proc Natl Acad Sci U S A. 1991 Jan 1;88(1):263–267. doi: 10.1073/pnas.88.1.263. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Paro R. Imprinting a determined state into the chromatin of Drosophila. Trends Genet. 1990 Dec;6(12):416–421. doi: 10.1016/0168-9525(90)90303-n. [DOI] [PubMed] [Google Scholar]
  23. Pearce J. J., Singh P. B., Gaunt S. J. The mouse has a Polycomb-like chromobox gene. Development. 1992 Apr;114(4):921–929. doi: 10.1242/dev.114.4.921. [DOI] [PubMed] [Google Scholar]
  24. Rastelli L., Chan C. S., Pirrotta V. Related chromosome binding sites for zeste, suppressors of zeste and Polycomb group proteins in Drosophila and their dependence on Enhancer of zeste function. EMBO J. 1993 Apr;12(4):1513–1522. doi: 10.1002/j.1460-2075.1993.tb05795.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Reijnen M. J., Hamer K. M., den Blaauwen J. L., Lambrechts C., Schoneveld I., van Driel R., Otte A. P. Polycomb and bmi-1 homologs are expressed in overlapping patterns in Xenopus embryos and are able to interact with each other. Mech Dev. 1995 Sep;53(1):35–46. doi: 10.1016/0925-4773(95)00422-x. [DOI] [PubMed] [Google Scholar]
  26. Schul W., Groenhout B., Koberna K., Takagaki Y., Jenny A., Manders E. M., Raska I., van Driel R., de Jong L. The RNA 3' cleavage factors CstF 64 kDa and CPSF 100 kDa are concentrated in nuclear domains closely associated with coiled bodies and newly synthesized RNA. EMBO J. 1996 Jun 3;15(11):2883–2892. [PMC free article] [PubMed] [Google Scholar]
  27. Simon J., Chiang A., Bender W. Ten different Polycomb group genes are required for spatial control of the abdA and AbdB homeotic products. Development. 1992 Feb;114(2):493–505. doi: 10.1242/dev.114.2.493. [DOI] [PubMed] [Google Scholar]
  28. Simon J. Locking in stable states of gene expression: transcriptional control during Drosophila development. Curr Opin Cell Biol. 1995 Jun;7(3):376–385. doi: 10.1016/0955-0674(95)80093-x. [DOI] [PubMed] [Google Scholar]
  29. Stuurman N., de Graaf A., Floore A., Josso A., Humbel B., de Jong L., van Driel R. A monoclonal antibody recognizing nuclear matrix-associated nuclear bodies. J Cell Sci. 1992 Apr;101(Pt 4):773–784. doi: 10.1242/jcs.101.4.773. [DOI] [PubMed] [Google Scholar]
  30. Wismar J., Löffler T., Habtemichael N., Vef O., Geissen M., Zirwes R., Altmeyer W., Sass H., Gateff E. The Drosophila melanogaster tumor suppressor gene lethal(3)malignant brain tumor encodes a proline-rich protein with a novel zinc finger. Mech Dev. 1995 Sep;53(1):141–154. doi: 10.1016/0925-4773(95)00431-9. [DOI] [PubMed] [Google Scholar]
  31. Zink B., Paro R. In vivo binding pattern of a trans-regulator of homoeotic genes in Drosophila melanogaster. Nature. 1989 Feb 2;337(6206):468–471. doi: 10.1038/337468a0. [DOI] [PubMed] [Google Scholar]
  32. van Lohuizen M., Frasch M., Wientjens E., Berns A. Sequence similarity between the mammalian bmi-1 proto-oncogene and the Drosophila regulatory genes Psc and Su(z)2. Nature. 1991 Sep 26;353(6342):353–355. doi: 10.1038/353353a0. [DOI] [PubMed] [Google Scholar]
  33. van Lohuizen M., Verbeek S., Scheijen B., Wientjens E., van der Gulden H., Berns A. Identification of cooperating oncogenes in E mu-myc transgenic mice by provirus tagging. Cell. 1991 May 31;65(5):737–752. doi: 10.1016/0092-8674(91)90382-9. [DOI] [PubMed] [Google Scholar]
  34. van der Lugt N. M., Alkema M., Berns A., Deschamps J. The Polycomb-group homolog Bmi-1 is a regulator of murine Hox gene expression. Mech Dev. 1996 Aug;58(1-2):153–164. doi: 10.1016/s0925-4773(96)00570-9. [DOI] [PubMed] [Google Scholar]
  35. van der Lugt N. M., Domen J., Linders K., van Roon M., Robanus-Maandag E., te Riele H., van der Valk M., Deschamps J., Sofroniew M., van Lohuizen M. Posterior transformation, neurological abnormalities, and severe hematopoietic defects in mice with a targeted deletion of the bmi-1 proto-oncogene. Genes Dev. 1994 Apr 1;8(7):757–769. doi: 10.1101/gad.8.7.757. [DOI] [PubMed] [Google Scholar]

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