Copg2 (coatomer protein complex subunit gamma) was reported to be preferentially maternally expressed in adult
brain and in whole embryos of C57BL/6J x Mus musculus molossinus reciprocal hybrid crosses (Lee
YJ et al, 2000). Two
antisense transcripts Copg2AS (Lee
YJ et al, 2000) and Copg2AS2 (Yun J et al, 2003) have been reported. Copg2AS2 was exclusively expressed from the maternal allele.
However, in the interspecific hybrid of C57BL/6 x M. spretus Copg2 was biallelically expressed in
month-old offspring despite the presence of a differentially methylated region (DMR) in the CpG
island, suggesting Copg2 expression is subject to variable epigenetic control in mouse species (Yun J et al, 2003).
MacIsaac JL et al (2012) reported that allelic usage of Copg2 is
regulated by a variant of Mest locus called MestXL. MestXL is transcribed downstream of Copg2 and
the authors showed Copg2 was preferentially maternally expressed in tissues that express MestXL (the
developing central nervous system) and truncation of MestXL resulted in loss of imprinting.
In contrast human COPG2 was reported to be paternally expressed (disputed, see human 7q). Copg2 is
adjacent to Mest.