| Imprinted genes are a small proportion of genes on the genome showing parent-of-origin-specific silencing. Up to now, more than 100 imprinted genes have been identified in mouse. Most of them are expressed from the maternal allele and the others from the paternal allele. The first paternally expressed imprinted gene Zdbf2 on mouse chromosome 1 was identified by Kobayashi et al using parthenogenetic embryos in 2009. In our research, EST of candidate imprinted genes was searched in the area closed to Zdbf2 according to the characteristic feature that imprinted genes are generally physically linked in clusters with other ones on chromosomes, and the isolation, identification and expression analysis of the EST——CJ051953 were investigated.Strain cross of C57BL/6J and ICR was used as experimental material to achieve imprinting identification. Expression of parental alleles were analysed using direct sequencing of RT-PCR based on SNP. The result showed that CJ051953 which named Peg14 (paternal expression gene 14) was biased in favor of the paternal allele and presented tissue-specific and developmental stage-specific expression profiles. Whole-mount in situ hybridization showed that strong signal of Peg14 appeared in the rhombencephalon, facial mesenchyme, neural tube at E9.5 and telencephalon, midbrain, rhombencephalon at E11.5. The result of in situ hybridization at E12.5 showed that the signal of Peg14 was relatively strong in the forebrain, midbrain,hindbrain and pituitary gland, while weaker in the spinal cord and somite. In addition, expression analysis was carried out by whole embryo semi-quantitative RT-PCR. The result showed that Peg14 expressed continuously in middle-late developmental stage. Peg14 exhibited the lowest expression level at E9.5 and reached the highest expression level at E11.5.This expression profile concentrated and imprinted in the brain indicate that Peg14 may have an important effect on the development of the nervous system of the mouse embryo. |
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