Mice lacking FABP9/PERF15 develop sperm head abnormalities but are fertile

The male germ cell specific fatty acid-binding protein 9 (FABP9/PERF15) is the major component of the murine sperm perforatorium and perinuclear theca Based on its cytoskeletal association and sequence homology to myelin P2 (FABP8) it has been suggested that FABP9 tethers sperm membranes to the underlying cytoskeleton Furthermore its upregulation in apoptotic testicular germ cells and its increased phosphorylation status during capacitation suggested multiple important functions for FABP9 Therefore we investigated specific functions for FABP9 by means of targeted gene disruption in mice FABP9(-/-) mice were viable and fertile Phenotypic analysis showed that FABP9(-/-) mice had significant Increases in sperm head abnormalities (similar to 8% greater than their WT cohorts) in particular we observed the reduction or absence of the characteristic structural element known as the ventral spur in similar to 10% of FABP9(-/-) sperm However deficiency of FABP9 affected neither membrane tethering to the perinuclear theca nor the fatty acid composition of sperm Moreover epididymal sperm numbers were not affected in FABP9(-/-) mice Therefore we conclude that FABP9 plays only a minor role in providing the murine sperm head its characteristic shape and is not absolutely required for spermatogenesis or sperm function (C) 2010 Elsevier Inc All rights reserved