Th (Tyrosine hydroxylase) was maternally expressed in E13.5 placenta but biallelically expressed in
E13.3 embryo (Schulz
R et al, 2006).
Brideau et al reported Th to be imprinted and maternally expressed in the E17.5 mouse placenta. No
evidence of imprinting was detected in E17.5 brain from reciprocal crosses (Brideau
CM et al, 2010).
Golding et al. reported that Th displayed maternal expression in E7.5 embryo and placenta and E8.5
placenta, and preferential maternal expression in E9.5 and E12.5 placenta, but was biallelically
expressed in the corresponding embryonic tissues. These results suggest that Th shares a similar
expression pattern with the neighbouring genes Tssc4 and Cd81, with maternal expression in
extra-embryonic lineages but progressive biallelic expression in the embryo (Golding CM et al, 2011)
C and Bourc'his D (2010) have cautioned that maternal contamination of placental tissues may
cause apparent imprinted maternal expression and recommend that reports of placental-specific
imprinted maternal expression should be interpreted with care.