The detailed entries of the Imprinted Gene Catalogue database were created by Benjamin Tycko, Columbia University, New York and are updated by Ian Morison


Detailed entry for Gene:



Mouse ChrX




The paternal allele of Esx1 is repressed; maternal allele active, in mouse placenta (Li Y et al, 1998). Note: the inactivation of the entire X-chromosome shows a parent-of-origin dependence in the trophectoderm of mice, such that the paternal X is preferentially inactivated in placenta. The imprinting of Esx1 may result from this phenomenon.

Gene Product:

Esx1 encodes a paired-type homeobox protein, which is highly expressed only in placenta and male germ cells (Li Y et al, 1997). An Esx-1 orthologue, ESX1L, is also X-linked, but because of the lack of a parent-of-origin effect on X-inactivation in humans, it is not likely to be imprinted (Fohn LE et al, 2001).

Functional Data:

Esx1 exerts a negative influence on growth of the placenta at early stages of development (placentas of Esx1-knockout conceptuses are larger). But this gene has a net positive effect on fetal growth at later stages, with fetal size reduced in the knockout, probably due to placental pathology (Li Y et al, 1998).


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