AGRP2

It determined by characterizing the ability of the folded zebrafish protein to inhibit the dose–response curve of α-MSH at the cloned zebrafish melanocortin receptors.

AgRP2 was a potent antagonist of the MC1R but showed little activity at MC4R and no antagonist activity at MC3R. Together with the data on regulation of agrp2 gene expression, these findings imply distinct roles for AgRP and AgRP2.

We can characterized the background adaptation response of zebrafish embryos cultured on white, gray, or black backgrounds from fertilization until 4 dpf. The identity of the pigmented spots as individual melanocytes was validated by identification of individual nuclei under high magnification using a compound microscope.

Analysis of the promoter region of the zebrafish AgRP2 gene identified elements involved in pineal-specific expression, including PIPE, E-box, and PCE elements. A study argue that the biological activities mediated by agrp2 are mediated by expression of the protein by the pineal.

Leptin inhibits AgRP2/NPY neurons and stimulates anorexigenic POMC neurons, thus promoting increased energy expenditure, decreased food intake, and a negative energy balance.

The agrp2 gene was expressed in the pineal gland in a previously uncharacterized subgroup of cells. Additionally, agrp2 was expressed in a small group of neurons in the preoptic area that project directly towards the pituitary and form an interface with the pituitary vasculature, suggesting that preoptic AgRP2 neurons are hypophysiotropic.

Zebrafish agrp2 mRNA is expressed in the pineal gland and was suggested, on the basis of morpholino-mediated knock-down experiments, to regulate background pigment adaptation for camouflage. Pineal gland expression of agrp2 was reported in sea bass, and we have also detected its expression in the pineal gland of Nile tilapia and rainbow trout. This suggests a conserved pineal gland expression of agrp2 among teleosts.

Direct synaptic connection can exist between AgRP1 and AgRP2 neurons in the hypothalamus, suggesting communication and coordination between AgRP1 and AgRP2 neurons and, therefore, probably also between the processes they regulate.

It is able to increases food intake when ubiquitously overexpressed or when administered centrally. AgRP-deficiency, on the other hand, leads to increased metabolic rate and a longer lifespan when mice consume a high fat diet.

To visualize AgRP2 neurons, employed the bacterial artificial chromosome (BAC) transgenesis approach to express fluorescent markers within these neurons. To increase the utility of the generated transgenic lines, we employed the Gal4-VP16 transactivation system, generating BACs in which Gal4-VP16 is under the control of agrp2 regulatory regions.