Deletion of the gene encoding H-FABP/MDGI has no overt effects in the mammary gland

Heart fatty acid binding protein (H-FABP) is expressed abundantly in the ma mmary gland. A number of in vitro studies have shown that H-FABP is functio nally indistinguishable from a factor isolated from this organ, termed mamm ary derived growth inhibitor (MDGI), which specifically inhibits the prolif eration of mammary tissue. We have previously shown that over-expression of H-FABP/MDGI in the mammary gland of transgenic mice has no discernable eff ects on cell proliferation or differentiation. In this report we describe k nockout mouse in which the H-FABP/MDGI gene has been specifically disrupted . The mice exhibit no overt phenotype in the mammary gland, and we conclude that this gene does not play a specific role in regulating the normal deve lopment or function of this tissue.