[Abstract Title]. - Society for Neuroscience

Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 278.15/MM8
Topic: E.01.e. Sexual differences
Support: R01MH072956
Title: Sex differences in the expression of Nuclear Receptor Corepessor (NCoR) in the rat
amygdala during development
Authors: *H. M. JESSEN 1 , M. H. KOLODKIN 2 , A. P. AUGER 1 ;
1 Dept Psychol, 2 Neurosci. Training Program, Univ. Wisconsin Madison, Madison, WI
Abstract: Steroid hormones play an important role in the developing rat brain, causing many
physiological and behavioral changes. Steroid hormone action is regulated at the level of the
DNA through a balance of recruitment of complexes which cause acetylation of histones and
increases in gene expression and through the recruitment of complexes, such as corepressors (i.e.
NCoR), which cause deacetylation and decreases in gene expression. Methyl-CpG-binding
protein 2 (MeCP2), which is thought to cause transcriptional repression through the recruitment
of corepressors and consequent deacetylation of histones, has been shown to have sex differences
in the developing rat brain. Females have been shown to express higher levels of MeCP2 mRNA
and protein in the amygdala and ventral medial hypothalamus (VMH), but not the pre optic area
(POA) on postnatal day 1 (PN1). This parallels our previous results, showing that females
express higher levels of the corepressor NCoR mRNA in the VMH but not the POA on PN1 as
compared to males. However, we have not investigated the levels of NCoR in the amygdala. We
used real-time RT-PCR to examine potential sex differences in NCoR in the amygdala of the
developing rat brain. On PN1 we have found that within the amygdala females express a greater
relative amount of NCoR mRNA as compared to males, interestingly this difference is still
present on post natal day 10 (PN10). The function of NCoR during this sensitive period may be
to protect females from steroid hormones or steroid hormones may act by decreasing NCoR
which would lead to a deaccetylation of histones resulting in an increase in gene expression.
Taken together these data suggest a dynamic model of chromatin remodeling which may drive
sex differences in the developing rat brain.
Disclosures: H.M. Jessen , None; A.P. Auger, None; M.H. Kolodkin, None.
Poster
278. Sex Differences I
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm