Biallelic expression of Tssc4, Nap1l4, Phlda2 and Osbpl5 in adult cattle.

Genomic imprinting of the Cdkn1c/Kcnq1ot1 region shows lack of conservation between human and mouse. This region has been reported to be associated with Beckwith-Wiedemann syndrome (BWS) and cancer. To increase our understanding of imprinted genes in bovine Cdkn1c/Kcnq1ot1 imprinting cluster, we assessed the imprinting status of four cattle genes (Tssc4,Nap1l4, Phlda2 and Osbpl5) in seven types of tissues: heart, liver, spleen, lung, kidney, skeletal muscle and subcutaneous fat using polymorphism-based sequencing approach. It was found that all the four genes showed biallelic expression in tissues in which transcripts were detected. Nap1l4 and Tssc4 were detected in all examined tissues, while the expression of Phlda2 and Osbpl5 was tissue-specific. Phlda2 was not detected in heart and subcutaneous fat, and Osbpl5 was not detected in spleen and skeletal muscle. In addition, identification of species-specific imprinted genes is necessary to understand the evolution of genomic imprinting and to elucidate mechanisms leading to allele-specific expression.