Nap1l4 (Nap2) shows preferential expression of the maternal allele, mainly in the placenta (Engemann
S et al, 2000).
Previously, the same group (Paulsen M et al, 1998) had reported biallelic expression in multiple fetal and adult
D et al (2004) imply that their results confirm
paternal repression in the placenta but the results as shown in Figure 1 are unconvincing.
However, Okae H et al, (2012) provided
strong evidence of negligible expression of Nap1l4 by qPCR and whole transcriptome sequencing in E
13.5 placentas. They suggest that this gene is not imprinted. This is concordant with Proudhon and Bourc'his, (2010) caution that maternal contamination of placental tissues may
cause apparent imprinted maternal expression.