HOXA5 is targeted by cell-type-specific CpG island methylation in normal cells and during the development of acute myeloid leukaemia.

HOXA5 is a member of the HOX gene family, which is known to play key roles during embryonic development and in differentiation of adult cells. In addition, HOXA5 has been implicated as a tumour suppressor in breast cancer and shown to transactivate the p53 gene. CpG island methylation is a common mechanism of gene inactivation in tumour cells, but is rarely involved in control of cell-type-specific (CTS) expression in normal cells. However, here we demonstrate that HOXA5 is one of a small number of genes whose CTS expression pattern is controlled by CTS CpG island methylation in normal cells. Furthermore, chromatin immunoprecipitation analysis identified novel patterns of histone modifications associated with DNA methylation of HOXA5. High levels of methylation of histone residues (lysine 9 and 36 of histone H3) previously associated with transcriptional repression were present in the unmethylated, actively transcribing state, and were then reduced following DNA methylation and gene inactivation. Alterations to the normal patterns of HOXA5 gene methylation were also observed in tumour cells. Quantitative analysis of HOXA5 methylation identified the presence of limited methylation in all of the breast, lung and ovarian tumours examined. However, methylation levels in these three tumour types were nearly always low and comparable with that detected in the corresponding normal tissue. In contrast, acute myeloid leukaemia (AML) samples frequently (60% of samples) exhibited very high methylation levels, far greater than that seen in normal haematopoietic cells, suggesting a role for hypermethylation of HOXA5 in the development of AML, consistent with its previously identified role in haematopoietic differentiation.

[1]  U. Bunz.  How Are Alkynes Scrambled? , 2005, Science.

[2]  G. Strathdee,et al.  Control of gene expression by CpG island methylation in normal cells. , 2004, Biochemical Society transactions.

[3]  H. Cedar,et al.  A stepwise epigenetic process controls immunoglobulin allelic exclusion , 2004, Nature Reviews Immunology.

[4]  S. Sukumar,et al.  HOXA5-Induced Apoptosis in Breast Cancer Cells Is Mediated by Caspases 2 and 8 , 2004, Molecular and Cellular Biology.

[5]  Robert Brown,et al.  Cell type-specific methylation of an intronic CpG island controls expression of the MCJ gene. , 2003, Carcinogenesis.

[6]  Mark Johnston,et al.  Set2-Catalyzed Methylation of Histone H3 Represses Basal Expression of GAL4 in Saccharomyces cerevisiae , 2003, Molecular and Cellular Biology.

[7]  B. Davies,et al.  Immortalisation of human ovarian surface epithelium with telomerase and temperature-sensitive SV40 large T antigen. , 2003, Experimental cell research.

[8]  I. Gut,et al.  Analysis and quantification of multiple methylation variable positions in CpG islands by Pyrosequencing. , 2003, BioTechniques.

[9]  T. A. Lister,et al.  Genome‐wide analysis of acute myeloid leukemia with normal karyotype reveals a unique pattern of homeobox gene expression distinct from those with translocation‐mediated fusion events , 2003, Genes, chromosomes & cancer.

[10]  A. Razin,et al.  Methylation of HoxA5 and HoxB5 and its relevance to expression during mouse development. , 2003, Gene.

[11]  J. Issa,et al.  Critical Role of Histone Methylation in Tumor Suppressor Gene Silencing in Colorectal Cancer , 2003, Molecular and Cellular Biology.

[12]  J. Herman,et al.  Dependence of histone modifications and gene expression on DNA hypermethylation in cancer. , 2002, Cancer research.

[13]  E. Ballestar,et al.  Allele‐specific histone lysine methylation marks regulatory regions at imprinted mouse genes , 2002, The EMBO journal.

[14]  Peter A. Jones,et al.  Histone H3-lysine 9 methylation is associated with aberrant gene silencing in cancer cells and is rapidly reversed by 5-aza-2'-deoxycytidine. , 2002, Cancer research.

[15]  John T. Dimos,et al.  A Stem Cell Molecular Signature , 2002, Science.

[16]  Hong Duan,et al.  Role for DNA methylation in the control of cell type–specific maspin expression , 2002, Nature Genetics.

[17]  Michael J. Terry,et al.  HOX gene clusters are hotspots of de novo methylation in CpG islands of human lung adenocarcinomas , 2002, Oncogene.

[18]  T. Kouzarides.  Histone methylation in transcriptional control. , 2002, Current opinion in genetics & development.

[19]  P. Grant,et al.  Set2 Is a Nucleosomal Histone H3-Selective Methyltransferase That Mediates Transcriptional Repression , 2002, Molecular and Cellular Biology.

[20]  P. Becker,et al.  Histone acetylation: a switch between repressive and permissive chromatin , 2002, EMBO reports.

[21]  S. Elgin,et al.  Epigenetic Codes for Heterochromatin Formation and Silencing Rounding up the Usual Suspects , 2002, Cell.

[22]  C. Allis,et al.  Parent-specific complementary patterns of histone H3 lysine 9 and H3 lysine 4 methylation at the Prader-Willi syndrome imprinting center. , 2001, American journal of human genetics.

[23]  M. Cantile,et al.  Homeobox genes in normal and malignant cells , 2001, Journal of cellular physiology.

[24]  C. Plass,et al.  Methylation matters , 2001, Journal of medical genetics.

[25]  S. Hooi,et al.  Differential expression of Hox A5 in human colon cancer cell differentiation: a quantitative study using real-time RT-PCR. , 2001, International journal of oncology.

[26]  Karl Mechtler,et al.  Methylation of histone H3 lysine 9 creates a binding site for HP1 proteins , 2001, Nature.

[27]  D. Botstein,et al.  Genomic binding sites of the yeast cell-cycle transcription factors SBF and MBF , 2001, Nature.

[28]  S. Sukumar,et al.  Compromised HOXA5 function can limit p53 expression in human breast tumours , 2000, Nature.

[29]  T. Nakano,et al.  In Vitro Proliferation Potential of AC133 Positive Cells in Peripheral Blood , 2000, Stem cells.

[30]  A. Bird,et al.  Methylation-Induced Repression— Belts, Braces, and Chromatin , 1999, Cell.

[31]  L. Jeannotte,et al.  Loss of Hoxa5 gene function in mice perturbs intestinal maturation. , 1999, American Journal of Physiology - Cell Physiology.

[32]  P. Malik,et al.  Constitutive HOXA5 expression inhibits erythropoiesis and increases myelopoiesis from human hematopoietic progenitors. , 1999, Blood.

[33]  J. Gasson,et al.  Characterization of HOX gene expression during myelopoiesis: role of HOX A5 in lineage commitment and maturation. , 1999, Blood.

[34]  G. Strathdee,et al.  A role for methylation of the hMLH1 promoter in loss of hMLH1 expression and drug resistance in ovarian cancer , 1999, Oncogene.

[35]  P. Laird,et al.  COBRA: a sensitive and quantitative DNA methylation assay. , 1997, Nucleic acids research.

[36]  R. Brown,et al.  Microsatellite instability, apoptosis, and loss of p53 function in drug-resistant tumor cells. , 1996, Cancer research.

[37]  R Holliday,et al.  DNA modification mechanisms and gene activity during development , 1975, Science.

[38]  John J. Wyrick,et al.  Genome-wide location and function of DNA binding proteins. , 2000, Science.

[39]  P. Avner,et al.  X-chromosome inactivation in mammals. , 1997, Annual review of genetics.

[40]  A. Bird.  The relationship of DNA methylation to cancer. , 1996, Cancer surveys.