Monoallelic gene expression, resulting from genomic imprinting, appears to have important consequences both in normal development and in human genetic disease and cancer. However, to date there have been very few studies of monoallelic gene expression at defined loci. We have shown that the human H19 gene, at chromosome 11p15, is monoallelically expressed. The 11p15 region is of particular interest in that maternal alleles are commonly deleted in childhood tumors and the region is therefore predicted to contain one or more imprinted tumor suppressor genes. We plan to study the mechanism and consequences of monoallelic gene expression in humans, focusing on H19 and flanking genes, and to explore strategies for isolating additional imprinted genes. To determine whether 11p15 imprinting is regional or local we will clone the genes immediately flanking H19 and test them for monoallelic expression. We will test the possible role of DNA methylation in imprinting by analyzing allele-specific methylation in and around the H19 gene and by carrying out functional assays for the effect of methylation on H19 expression. We will search for candidate imprinting """"""""initiator"""""""" sequences in H19 and flanking DNA using a transfection assay in embryonal stem cells. We will characterize a novel phenomenon, tissue-specific somatic allele switching, which we have observed for human H19 and which suggests methylation threshold and feedback effects in maintenance of monoallelic gene expression. To explore the biological function of H19, and to determine whether this gene might have tumor suppressor activity, we will examine the ability of inducible H19 expression vectors to revert the phenotype of Wilms' tumor and embryonal rhabdomyosarcoma cells. Finally, to isolate additional imprinted genes, we will pursue a candidate gene approach in humans and, concurrently, develop a general strategy, based on arbitrarily-primed polymerase chain reaction (AP-RCR), to clone imprinted genes from interspecific mouse hybrids.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA060765-03
Application #
2101533
Study Section
Pathology B Study Section (PTHB)
Project Start
1993-07-15
Project End
1998-05-31
Budget Start
1995-06-01
Budget End
1996-05-31
Support Year
3
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Columbia University (N.Y.)
Department
Pathology
Type
Schools of Medicine
DUNS #
167204994
City
New York
State
NY
Country
United States
Zip Code
10032
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Saxena, Anjana; Morozov, Pavel; Frank, Dale et al. (2002) Phosphoinositide binding by the pleckstrin homology domains of Ipl and Tih1. J Biol Chem 277:49935-44
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Qian, N; Frank, D; O'Keefe, D et al. (1997) The IPL gene on chromosome 11p15.5 is imprinted in humans and mice and is similar to TDAG51, implicated in Fas expression and apoptosis. Hum Mol Genet 6:2021-9
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Moulton, T; Chung, W Y; Yuan, L et al. (1996) Genomic imprinting and Wilms' tumor. Med Pediatr Oncol 27:476-83

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