Transgenic Mice Expressing Green Fluorescent Protein under the Control of the Melanocortin-4 Receptor Promoter

The melanocortin-4 receptor (MC4-R) is an important regulator of energy homeostasis, and evidence suggests that MC4-R-expressing neurons are downstream targets of leptin action. MC4-Rs are broadly expressed in the CNS, and the distribution of MC4-R mRNA has been analyzed most extensively in the rat. However, relatively little is known concerning chemical profiles of MC4-R-expressing neurons. The extent to which central melanocortins act presynaptically or postsynaptically on MC4-Rs is also unknown. To address these issues, we have generated a transgenic mouse line expressing green fluorescent protein (GFP) under the control of the MC4-R promoter, using a modified bacterial artificial chromosome. We have confirmed that the CNS distribution of GFP-producing cells is identical to that of MC4-R mRNA in wild-type mice and that nearly all GFP-producing cells coexpress MC4-R mRNA. For example, cells coexpressing GFP and MC4-R mRNA were distributed in the paraventricular hypothalamic nucleus (PVH) and the dorsal motor nucleus of the vagus (DMV). MC4-R promotor-driven GFP expression was found in PVH cells producing thyrotropin-releasing hormone and in cholinergic DMV cells. Finally, we have observed that a synthetic MC3/4-R agonist, MT-II, depolarizes some GFP-expressing cells, suggesting that MC4-Rs function postsynaptically in some instances and may function presynaptically in others. These studies extend our knowledge of the distribution and function of the MC4-R. The transgenic mouse line should be useful for future studies on the role of melanocortin signaling in regulating feeding behavior and autonomic homeostasis.

Reduction of green fluorescent protein (GFP) expression and

IJMS, Free Full-Text

Loss of the melanocortin-4 receptor in mice causes dilated

Nutrients, Free Full-Text

The stimulatory G protein Gsα is required in melanocortin 4

Molecular Therapy of Melanocortin-4-Receptor Obesity by an

The stimulatory G protein Gsα is required in melanocortin 4

The stimulatory G protein Gsα is required in melanocortin 4

IJMS, Free Full-Text

Loss of the melanocortin-4 receptor in mice causes dilated