Hypothalamic expression of Peg3 gene is associated with maternal care differences between SM/J and LG/J mouse strains

Author(s)

Chiavegatto, Silvana ^{[1, 2, 3]} ; Sauce, Bruno ^[4] ; Ambar, Guilherme ^[2] ; Cheverud, James M. ^[5] ; Peripato, Andrea C. ^{[6, 4]}

Affiliation

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Pharmacol, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Sch Med, Dept & Inst Psychiat, Sao Paulo - Brazil

^[3] Natl Inst Dev Psychiat Childhood & Adolescence IN, Sao Paulo - Brazil

^[4] Univ Fed Sao Carlos, Dept Genet & Evolut, Biol Sci & Hlth Ctr, BR-13565905 Sao Carlos, SP - Brazil

^[5] Washington Univ, Sch Med, Dept Anat & Neurobiol, St Louis, MO 63110 - USA

^[6] Univ Fed Sao Paulo, Dept Biosci, Santos, SP - Brazil

• Document type: Journal article
• Source: BRAIN AND BEHAVIOR; v. 2, n. 4, p. 365-376, JUL 2012.
• Web of Science Citations: 9

Abstract

Maternal care is essential in mammals, and variations in the environment provided by mothers may directly influence the viability of newborns and emotional behavior later in life. A previous study investigated genetic variations associated with maternal care in an intercross of LG/J and SM/J inbred mouse strains and identified two single-locus QTLs (quantitative trait loci). Here, we selected three candidate genes located within these QTLs intervals; Oxt on chromosome 2, and FosB and Peg3 on chromosome 7 and tested their association with maternal care. LG/J females showed impaired postpartum nest building and pup retrieval, a one-day delay in milk ejection, reduced exploratory activity, and higher anxiety-like behavior when compared to SM/J females. The nucleotide sequences of Oxt and FosB were similar between strains, as were their hypothalamic expression levels. Conversely, Peg3 nucleotide sequences showed four nonsynonymous replacement substitutions on LG/J dams, T11062G, G13744A, A13808G, and G13813A, and a 30 base pair (10 aa) in tandem repeat in the coding region with three copies in SM/J and five copies in LG/J. Maternal care impaired LG/J mothers express 37% lower Peg3 mRNA levels in the hypothalamus on the second postpartum day. We also found an association of the Peg3 repeat-variant and poor maternal care in F-2 heterozygote females derived from a LG/J x SM/J intercross. These results may suggest that the maternally imprinted Peg3 gene is responsible for the single-locus QTL on chromosome 7 that has been shown to influence maternal care in these strains. Furthermore, these data provide additional support for an epigenetic regulation of maternal behavior. (AU)

• FAPESP's process: 09/01333-8 - Chronic administration of 13-cis-retinoic acid (isotretinoin) in adolescent male mice: emotional behaviors and mRNA levels of several brain 5-HT receptors
• Grantee: Silvana Chiavegatto
• Support Opportunities: Regular Research Grants