Social and maternal behavior in mesoderm specific transcript (Mest)-deficient mice

by Rea P. Anunciado-Koza, J. Patrizia Stohn, Arturo Hernandez, Robert A. Koza

Mesoderm specific transcript (Mest)/paternally expressed gene-1 (Peg1) is an imprinted gene expressed predominantly from the paternal allele. Aberrations in maternal behavior were previously reported in a Mest global knockout mouse (Mest^tm1Masu). In this study, we performed in-depth social and maternal behavioral testing in a mouse model of Mest inactivation developed in our laboratory (Mest^tm1.2Rkz). Mice with paternal allele inactivation (Mest^pKO) did not show anxiety after testing in the elevated plus maze, open field trial, and marble burying; nor depression-like behaviors in the tail suspension test. Mest^pKO showed normal social behaviors and memory/cognition in the three-chamber box test and the novel object recognition test, respectively. Primiparous Mest^pKO and Mest^gKO (biallelic Mest inactivation) female mice exhibited normal nest building and maternal behavior; and, virgin Mest^pKO and Mest^gKO female mice showed normal maternal instinct. Analyses of gene expression in adult hypothalamus, embryonic day 14.5 whole brain and adult whole brain demonstrated full abrogation of Mest mRNA in Mest^pKO and Mest^gKO mice with no effect on miR-335 expression. Our data indicates no discernible impairments in object recognition memory, social behavior or maternal behavior resulting from loss of Mest. The basis for the differences in maternal phenotypic behaviors between Mest^tm1Masu and Mest^tm1.2Rkz is not known.