A subset of genes in mammals is regulated by genomic imprinting, a process that results in unequal expression of the maternal and paternal alleles of this class of genes. Imprinted genes are hypothesized to expiain why nuclear contributions from both parents are required for normal mammalian development. Furthermore, imprinting plays a role in the transmission of a number of human genetic diseases, including Beckwith-Wiedemann Syndrome (BWS), Silver-Russell Syndrome (SRS), Prader-Willi and Angelman Syndrome, in that the sex ofthe parent that transmits the affected gene(s) determines whether offspring will develop the disease. Aben-ant imprinted gene expression is also involved in the establishment or progression of cancers, inciuding Wilms tumors. The objective of this proposal is to investigate the- mechanism by which parental identity of imprinted genes is established and maintained. The studies will employ the conserved H19/lgf2 locus. The imprinting of H19, which produces a non-coding RNA from the maternally-derived allele, and the linked and oppositely imprinted growth-promoting Igf2 gene is mediated through the 2 kb imprinting control region (ICR) and shared enhancers. The ICR acts as a methylation- senstitive, CTCF-dependent insulator. When unmethylated on the maternal allele, the insulator allows H19 exclusive access to the enhancers. In contrast, a methylated paternal insulator enables Igf2 to engage the enhancers. This proposal will investigate the mechanism of H19/lgf2 imprinting through the following experiments. Individuals with BWS, sporadic Wilms tumors and SRS have been identified that have microdeletions and epimutations in the human ICR and aberrant imprinted regulation of H19 and Igf2. We wiil generate mouse models and human IPS cells with these mutations and study the mechanism of loss of imprinting. We will also investigate the function of a conserved non-coding RNA located between H19 and Igf2 and the H19 micro RNA, miR-675, using mutations constructed at the mouse locus. We will additionally explore the role of TET1 in the establishment and erasure of ICR methylation. Last, the imprinting mechanism will be studied at the Grb10 locus, which may employ aspects of H19 imprinted regulation.

Public Health Relevance

(See insfruc:tions): Imprinted genes are critical for normal mammalian development, behavior and energy homeostasis. This genes have genetic or epigenetic mutations in a number of human syndromes and cancer. The experiments in this proposal will model such newly identified mutations in individuals with Beckwith-Wiedemann Syndrome and Silver-Russell Syndrome, providing a better understanding ofthe etiology ofthe disease. PROJECT/PERFORIVIANCE SITE(S) (if additional space Is needed, use

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37GM051279-26
Application #
9742493
Study Section
Special Emphasis Panel (NSS)
Program Officer
Carter, Anthony D
Project Start
2016-08-01
Project End
2021-07-31
Budget Start
2019-08-01
Budget End
2020-07-31
Support Year
26
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
SanMiguel, Jennifer M; Bartolomei, Marisa S (2018) DNA methylation dynamics of genomic imprinting in mouse development. Biol Reprod 99:252-262
Freschi, Andrea; Hur, Stella K; Valente, Federica Maria et al. (2018) Tissue-specific and mosaic imprinting defects underlie opposite congenital growth disorders in mice. PLoS Genet 14:e1007243
Bernhardt, Miranda L; Stein, Paula; Carvacho, Ingrid et al. (2018) TRPM7 and CaV3.2 channels mediate Ca2+ influx required for egg activation at fertilization. Proc Natl Acad Sci U S A 115:E10370-E10378
SanMiguel, Jennifer M; Abramowitz, Lara K; Bartolomei, Marisa S (2018) Imprinted gene dysregulation in a Tet1 null mouse model is stochastic and variable in the germline and offspring. Development 145:
Hur, Stella K; Freschi, Andrea; Ideraabdullah, Folami et al. (2016) Humanized H19/Igf2 locus reveals diverged imprinting mechanism between mouse and human and reflects Silver-Russell syndrome phenotypes. Proc Natl Acad Sci U S A 113:10938-43
Ginart, Paul; Kalish, Jennifer M; Jiang, Connie L et al. (2016) Visualizing allele-specific expression in single cells reveals epigenetic mosaicism in an H19 loss-of-imprinting mutant. Genes Dev 30:567-78
Zhong, Cuiqing; Yin, Qi; Xie, Zhenfei et al. (2015) CRISPR-Cas9-Mediated Genetic Screening in Mice with Haploid Embryonic Stem Cells Carrying a Guide RNA Library. Cell Stem Cell 17:221-32
Plasschaert, Robert N; Bartolomei, Marisa S (2015) Tissue-specific regulation and function of Grb10 during growth and neuronal commitment. Proc Natl Acad Sci U S A 112:6841-7
Ideraabdullah, Folami Y; Thorvaldsen, Joanne L; Myers, Jennifer A et al. (2014) Tissue-specific insulator function at H19/Igf2 revealed by deletions at the imprinting control region. Hum Mol Genet 23:6246-59
Weaver, Jamie R; Bartolomei, Marisa S (2014) Chromatin regulators of genomic imprinting. Biochim Biophys Acta 1839:169-77

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