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Analysis of two translocation breakpoints and identification of a negative regulatory element in patients with Rieger's syndrome. Birth Defects Res A Clin Mol Teratol 2004 Feb;70(2):82-91

Date

03/03/2004

Pubmed ID

14991915

DOI

10.1002/bdra.10154

Scopus ID

2-s2.0-1542366422 (requires institutional sign-in at Scopus site)   21 Citations

Abstract

BACKGROUND: Rieger's syndrome is an autosomal dominant disorder characterized by eye, tooth, and umbilical anomalies. A gene responsible for Rieger's syndrome, PITX2, has previously been cloned using two patients with balanced translocations, t(4;16) and t(4;11), with breakpoints that lie near the gene, but which do not interrupt it.

METHODS: We sequenced both breakpoint regions on chromosome 4 and screened this area for novel genes. Fluorescence in situ hybridization (FISH) was used to determine if PITX2 was still present on the 4:16 chromosome. Both the chromosome 16 and chromosome 11 breakpoints were cloned and sequenced using panhandle polymerase chain reaction (PHPCR). Transient transfection studies were performed to compare effects on a reporter gene between native chromosome 4 sequence and chromosome 11 sequence.

RESULTS: The region surrounding PITX2 on chromosome 4 is rich in repetitive elements, but no novel genes were identified. FISH demonstrated that PITX2 was intact on the 4:16 translocation chromosome. The PHPCR experiments demonstrated that the translocated regions of chromosomes 16 and 11 were repeat-rich, and transfection studies revealed a slight enhancer effect with the chromosome 4 sequence, and a strong silencer effect when the chromosome 11 sequence was present.

CONCLUSIONS: Given the lack of any novel genes near either breakpoint, changes in potential regulatory elements may be the best model to explain the loss of PITX2 expression in these patients and hence the Rieger's syndrome phenotype.

Author List

Trembath DG, Semina EV, Jones DH, Patil SR, Qian Q, Amendt BA, Russo AF, Murray JC

Author

Elena V. Semina PhD Chief, Professor in the Ophthalmology and Visual Sciences department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Abnormalities, Multiple
Cells, Cultured
Chromosome Breakage
Chromosomes, Human, Pair 11
Chromosomes, Human, Pair 16
Chromosomes, Human, Pair 4
Cloning, Molecular
Contig Mapping
Genes, Reporter
Humans
In Situ Hybridization, Fluorescence
Polymerase Chain Reaction
Regulatory Sequences, Nucleic Acid
Sequence Analysis, DNA
Syndrome
Transfection
Translocation, Genetic