The mouse coat color mutant, mahogunin, ring finger 1; mahoganoid (Mgrn1md), darkens coat color and decreases the obesity of Ay mice that ectopically overexpress agouti-signaling protein (ASP). This mutations and others in the Mgrn1 mahoganoid allelic series are due to large retroviral insertions. Overexpression of ASP inhibits the rise in cAMP levels in response to alpha-melanocyte-stimulating hormone, an MC4R agonist, by blocking ligand binding and by directing MC4R trafficking to the lysosome.
|Gene Symbol and Name||Mgrn1, mahogunin, ring finger 1|
|Strain of Origin||C3H/HeJ|
|General Note||The original md mutation arose in the C3H/HeJ strain. This gene is similar to mahogany (Atrnmg) in its effects on coat color, but causes less darkening of the back, ears, and tail of agouti mice (J:13379)(J:13791).|
|Molecular Note||The mutation in md has been attributed to a 5 kb retroviral insertion located in the intronic region 5' of exon 12. Northern analysis and RT-PCR indicate that the expression of transcript is greatly reduced in these mice.|