Identification And Characterization Of Two Novel Imprinted Transcripts Ak142849 And Ak003491 In The Mouse

Genomic imprinting is an epigenetic mechanism that causes genes to beexpressed from only one of the two parental alleles. The Dlk1-Dio3 imprinteddomain on mouse chromosome 12qF1 contains three paternally expressedprotein-coding genes: Dlk1, Rtl1, Dio3, several maternally expressed noncodingRNA genes: Meg3/Gtl2, Anti-Rtl1 , Meg8 , Irm, Meg9/Mirg, and a large number ofmicroRNAs and snoRNAs. Multiple cDNA clones derived from Riken librariesmap to the intergenic regions in this domain. In this study, we verified thematernal allele-specific expression of two intergenic transcripts AK142849 andAK003491 between anti-Rtl1 and Meg8 in this domain by SNP sequencing, anddetected their expression patterns during embryonic development by in situhybridization and quantitative real-time RT-PCR. The two novel imprintedtranscripts share a very similar expression pattern, at E9.5 their expressionsignals are mainly restrict to the forebrain, at E15.5 the mRNA signals can bemainly observed in brain, tongue, lung, liver, kidney and somite. From E12.5 toE18.5, the expression in brain and tongue increased, but in heart, lung, liver andkidney it decreased. This further expanded the number of known imprinted genesat this locus, and contributed to the better understanding of the organization andregulation of clustered noncoding RNA genes in the Dlk1-Dio3 domain.