Neuronal deletion of the T/EBP gene delay female puberty and causes premature reproductive senescence

MASTRONARDI C.; SMILEY G.; KUSAKABE T.; KAWAGUSHI A.; CABRERA, R.; MUNGENAST A.; KIMURA S.; OJEDA S.R.

San Diego. USA

Congreso; 34th Annual Meeting Society for Neurosciencies; 2004

NEURONAL DELETION OF THE T/EBP GENE DELAYS FEMALE PUBERTY AND CAUSES PREMATURE REPRODUCTIVE SENESCENCE C.Mastronardi1; G.Smiley1; T.Kusakabe2; A.Kawagushi2; R.Cabrera1; A.Mungenast1; S.Kimura2; S.R.Ojeda1* 1. Div Neurosci, ONPRC/OHSU, Beaverton, OR, USA 2. Lab Metabolism, NCI, Bethesda, MD, USA T/ebp (Nxk 2.1, TTF-1), a homeodomain gene required for diencephalic morphogenesis, remains postnatally expressed in discrete neuronal and glial subpopulations of the hypothalamus. The role that T/ebp may have in the neuroendocrine brain is unknown. Gene expression profiling of the nonhuman primate hypothalamus via cDNA arrays, followed by RealTime PCR verification, demonstrated that T/ebp mRNA levels increase during female puberty, suggesting that T/ebp might be involved in the control of mammalian puberty. To examine this hypothesis we employed mice in which neuronal T/ebp gene expression is conditionally disrupted. To achieve neuron-specific deletion of the T/ebp gene we crossed mutant mice in which exon 2 of the T/ebp gene is flanked by loxP sequences with animals in which Cre recombinase expression is controlled by the synapsin I promoter. Because only certain subsets of hypothalamic neurons express T/ebp postnatally, neuronal deletion of T/ebp is hypothalamic-specific. Cre-mediated disruption of the T/ebp gene in the hypothalamus, already evident at birth, became maximal by postnatal day 40. In situ hybridization and RealTime PCR verified the loss of T/ebp expression. Proenkephalin mRNA levels were increased in the T/ebp null hypothalamus, in agreement with the ability of T/ebp to suppress proenkephalin gene transcription. Although KO mice grew normally and had normal hypothalamic morphology, they exhibited delayed puberty (first ovulation), reduced reproductive capacity (number of litters), reduced fertility (number of pups per litter) and a much shorter reproductive life (50%) than control mice. These results suggest that T/ebp is a component of the transcriptional machinery that, operating within the neuroendocrine brain, controls female sexual development.Support Contributed By: NIH grants HD25123, U5418185, RR00163, Fogarty TW/HD00668