Potential novel mechanism for Axenfeld-Rieger syndrome: deletion of a distant region containing regulatory elements of PITX2. Invest Ophthalmol Vis Sci 2011 Mar;52(3):1450-9
Date
10/01/2010Pubmed ID
20881290Pubmed Central ID
PMC3101680DOI
10.1167/iovs.10-6060Scopus ID
2-s2.0-79955934874 (requires institutional sign-in at Scopus site) 41 CitationsAbstract
PURPOSE: Mutations in PITX2 are associated with Axenfeld-Rieger syndrome (ARS), which involves ocular, dental, and umbilical abnormalities. Identification of cis-regulatory elements of PITX2 is important to better understand the mechanisms of disease.
METHODS: Conserved noncoding elements surrounding PITX2/pitx2 were identified and examined through transgenic analysis in zebrafish; expression pattern was studied by in situ hybridization. Patient samples were screened for deletion/duplication of the PITX2 upstream region using arrays and probes.
RESULTS: Zebrafish pitx2 demonstrates conserved expression during ocular and craniofacial development. Thirteen conserved noncoding sequences positioned within a gene desert as far as 1.1 Mb upstream of the human PITX2 gene were identified; 11 have enhancer activities consistent with pitx2 expression. Ten elements mediated expression in the developing brain, four regions were active during eye formation, and two sequences were associated with craniofacial expression. One region, CE4, located approximately 111 kb upstream of PITX2, directed a complex pattern including expression in the developing eye and craniofacial region, the classic sites affected in ARS. Screening of ARS patients identified an approximately 7600-kb deletion that began 106 to 108 kb upstream of the PITX2 gene, leaving PITX2 intact while removing regulatory elements CE4 to CE13.
CONCLUSIONS: These data suggest the presence of a complex distant regulatory matrix within the gene desert located upstream of PITX2 with an essential role in its activity and provides a possible mechanism for the previous reports of ARS in patients with balanced translocations involving the 4q25 region upstream of PITX2 and the current patient with an upstream deletion.
Author List
Volkmann BA, Zinkevich NS, Mustonen A, Schilter KF, Bosenko DV, Reis LM, Broeckel U, Link BA, Semina EVAuthors
Ulrich Broeckel MD Chief, Center Associate Director, Professor in the Pediatrics department at Medical College of WisconsinBrian A. Link PhD Professor in the Cell Biology, Neurobiology and Anatomy department at Medical College of Wisconsin
Kala Schilter in the CTSI department at Medical College of Wisconsin - CTSI
Elena V. Semina PhD Chief, Professor in the Ophthalmology and Visual Sciences department at Medical College of Wisconsin
Natalya S. Zinkevich PhD Research Scientist I in the Medicine department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AnimalsAnimals, Genetically Modified
Anterior Eye Segment
Eye Abnormalities
Eye Diseases, Hereditary
Gene Deletion
Gene Duplication
Gene Expression
Homeodomain Proteins
Humans
In Situ Hybridization
Infant
Male
Mutation
Plasmids
Regulatory Elements, Transcriptional
Sequence Deletion
Transcription Factors
Zebrafish
