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Mol Cell Biol. 2005 Jul;25(13):5514-22.

A novel variant of Inpp5f is imprinted in brain, and its expression is correlated with differential methylation of an internal CpG island.

Author information

1
Department of Medical and Molecular Genetics, Guy's, King's and St. Thomas' School of Medicine, King's College London, 8th Floor, Guy's Tower, London SE1 9RT, United Kingdom.

Abstract

Using a tissue-specific microarray screen in combination with chromosome anomalies in the mouse, we identified a novel imprinted gene, Inpp5f_v2 on mouse chromosome 7. Characterization of this gene reveals a 3.2-kb transcript that is paternally expressed in the brain. Inpp5f_v2 is a variant of the related 4.7-kb transcript, Inpp5f, an inositol phosphatase gene that is biallelically expressed in the mouse. Inpp5f_v2 uses an alternative transcriptional start site within an intron of Inpp5f and thus has a unique alternative first exon. Whereas other imprinted transcripts have a unique first exon located within intron 1 of a longer transcript variant (such as at the Gnas and WT1 loci), Inpp5f_v2 is the first example of which we are aware in which the alternative first exon of an imprinted gene is embedded in a downstream intron (intron 15) of a transcript variant. The CpG island associated with the non-imprinted Inpp5f gene is hypomethylated on both alleles, a finding consistent with biallelic expression, whereas the CpG island present 5' of Inpp5f_v2 is differentially methylated on the maternal versus paternal alleles consistent with its imprinting status.

PMID:
15964807
PMCID:
PMC1156974
DOI:
10.1128/MCB.25.13.5514-5522.2005
[Indexed for MEDLINE]
Free PMC Article

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