A most interesting gene that we found more than tenfold up-regulated codes for an as yet not-well-characterized hypothetical human protein (LOC646627) carrying a phospholipase A2 inhibitor domain (PLA2-inh). The magnitude and kinetics of up-regulation of this gene corresponded exactly with GCNT3, suggesting that this gene was expressed in the same types of cells as GCNT3, most likely mucus-producing goblet cells and/or differentiating (immature) enterocytes. The amino acid sequence translated from our PLA2-inh EST showed an overall amino acid identity of 56%, and all cysteines aligned perfectly with cysteines of the human LOC646627 protein and of other proteins that bear a typical PLA2-inh domain. PLA2s comprise a diverse family of cytosolic and secreted enzymes that hydrolyze membrane phospholipids to free fatty acids. They play an important role in many exogenous and intracellular processes, ranging from fatty acid metabolism and lysis of membranes to the synthesis of arachidonic acid (A-acid), an essential precursor for the production of inflammatory mediators such as eicosanoids. Secreted PLA2s are calcium-dependent enzymes. Cytosolic PLA2s (cPLA2) can also be calcium-independent. A moderate increase in [Ca 2+ ] cyt mediated translocation of calcium-dependent cPLA2 to intracellular membranes where it hydrolyses phospholipids to A-acid [12] . A similar effect was observed after activation of the MS4A2 calcium-permeable cation channel (up-regulated here at 18 hpi, see above) on the surface of mast cells [14] . Perhaps, enhanced expression of a PLA2-inh in our study may be a countermeasure of specific intestinal epithelial cells to normalize and/or inhibit PLA2 enzyme activity in response to extra-and intracellular changes in [Ca 2+ ] evoked by rotavirus replication, either to protect specific cells from extra-and intracellular membrane-damage or to negatively regulate A-acid production. With respect to the latter process, we observed down-regulation of the enzymes CYP2C39 and ACSL3, which both utilize A-acid acid as substrate. Interestingly, the capsid protein of parvovirus possesses PLA2 activity [49] , and HMCV particles carry a cell-derived PLA2 activity [2] . For both viruses, PLA2 activity appeared to be essential for infectivity.