Transcriptional and epigenetic regulation of the integrin collagen receptor locus ITGA1-PELO-ITGA2.
The integrin collagen receptor locus on human chromosome 5q11.2 includes the integrin genes ITGA1 and ITGA2, and the cell cycle regulation gene PELO, embedded within ITGA1 intron 1. ITGA1 contains a CArG box that is bound by serum response factor (SRF), while PELO contains two Sp1 binding elements. A comparison of mRNA levels in megakaryocytic (MK) and non-megakaryocytic (non-MK) cell lines and an analysis of the transcriptional activity of promoter-LUC reporter gene constructs in transfected cells revealed that ITGA1 is selectively suppressed in the MK lineage. Sodium bisulfite genomic sequencing established that a CpG-rich ITGA1 promoter region (-209/+115) is fully methylated at 19 CpG sites in MK cells that do not express alpha1beta1, but completely demethylated in expressing cells. In vitro methylation of ITGA1 suppresses transcription, while treatment of megakaryocytic cells with 5-aza-2'-deoxycytidine, but not Trichostatin A, resulted in de novo expression of ITGA1. During thrombopoietin-induced in vitro differentiation of primary human cord blood mononuclear cells into megakaryocytes, we observed rapid, progressive CpG methylation of ITGA1, but not PELO or ITGA2. Thus, selective CpG methylation of the ITGA1 promoter is a specific feature of alpha1beta1 regulation that coincides with the initiation of megakaryocyte differentiation.
The Roon Research Center for Arteriosclerosis and Thrombosis, Division of Experimental Hemostasis and Thrombosis, Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
Yann
Y
Cheli
Sachiko
S
Kanaji
Beatrice
B
Jacquelin
Mei
M
Chang
Diane J
DJ
Nugent
Thomas J
TJ
Kunicki
D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002895:Chromosomes, Human, Pair 5 / Q000235:genetics / Q000378:metabolism*; D019175:DNA Methylation / Q000187:drug effects; D000077209:Decitabine; D004791:Enzyme Inhibitors / Q000494:pharmacology; D044127:Epigenesis, Genetic / Q000187:drug effects / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D039423:Integrin alpha1 / Q000096:biosynthesis* / Q000235:genetics; D039222:Integrin alpha1beta1 / Q000096:biosynthesis* / Q000235:genetics; D039421:Integrin alpha2 / Q000096:biosynthesis* / Q000235:genetics; D007438:Introns / Q000502:physiology; D020014:K562 Cells; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000378:metabolism; D008533:Megakaryocytes / Q000166:cytology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000502:physiology; D040641:Quantitative Trait Loci / Q000502:physiology*; D013926:Thrombopoietin / Q000494:pharmacology; D014158:Transcription, Genetic
D004791:Enzyme Inhibitors; D006877:Hydroxamic Acids; D039423:Integrin alpha1; D039222:Integrin alpha1beta1; D039421:Integrin alpha2; D009687:Nuclear Proteins; C012589:trichostatin A; D000077209:Decitabine; D013926:Thrombopoietin; D001374:Azacitidine