Authentic cell-specific and developmentally regulated expression of pro- opiomelanocortin genomic fragments in hypothalamic and hindbrain neurons of transgenic mice

• Autores: Young, J.I.; Otero, V.; Cerdán, M.G.; Falzone, T.L.; Cheng Chan, E.; Low, M.J.; Rubinstein, M.
• Año de publicación: 1998
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: J. Neurosci. 1998;18(17):6631-6640
• Materia: β- endorphin; Arcuate nucleus; Gene expression; Hypothalamus; Melanocortin; Neuron-specific expression; Pituitary; Pro-opiomelanocortin; Transgenic mice; melanocortin; animal cell; animal experiment; animal tissue; article; cell specificity; gene amplification; gene deletion; gene expression regulation; gene library; gene location; genome; hormonal regulation; hypothalamus; in situ hybridization; nonhuman; plasmid; polymerase chain reaction; priority journal; rhombencephalon; transgenic mouse; Animals; DNA Fragmentation; Gene Expression Regulation, Developmental; Genome; Hypothalamus; Mice; Mice, Transgenic; Neurons; Organ Specificity; Pro-Opiomelanocortin; Rhombencephalon
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

The pro-opiomelanocortin (POMC) gene is expressed in a subset of hypothalamic and hindbrain neurons and in pituitary melanotrophs and corticotrophs. POMC neurons release the potent opioid β-endorphin and several active melanocortins that control homeostasis and feeding behavior. POMC gene expression in the CNS is believed to be controlled by distinct cis- acting regulatory sequences. To analyze the transcriptional regulation of POMC in neuronal and endocrine cells, we produced transgenic mice carrying POMC27*, a transgene containing the entire 6 kb of the POMC transcriptional unit together with 13 kb of 5' flanking regions and 8 kb of 3' flanking regions: POMC27* was tagged with a heterologous 30 bp oligonucleotide in the third exon. In situ hybridization studies showed an accurate cell-specific pattern of expression of POMC27* in the arcuate nucleus and the pituitary. Hypothalamic mRNA-positive neurons colocalized entirely with β-endorphin immunoreactivity. No ectopic transgenic expression was detected in the brain. Deletional analyses demonstrated that neuron-specific expression of POMC transgenes required distal 5' sequences localized upstream of the pituitary- responsive proximal cis-acting elements that were identified previously. POMC27* exhibited a spatial and temporal pattern of expression throughout development that exactly paralleled endogenous POMC. RNase protection assays revealed that POMC27* expression mimicked that of POMC in different areas of the CNS and most peripheral organs with no detectable ectopic expression. Hormonal regulation of POMC27* and POMC was identical in the hypothalamus and pituitary. These results show that distal 5' sequences of the POMC gene located between -13 and -2 kb target expression into the CNS of transgenic mice in a precise neuron-specific, developmentally and hormonally regulated manner.
Fil:Young, J.I. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Otero, V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Cerdán, M.G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Falzone, T.L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Rubinstein, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.