Measurements of villus length indicated that considerable numbers of epithelial cells were lost from the tip of the villi, including (infected) mature enterocytes. In part, down-regulation of genes involved in transport of ions and nutrients over the membranes of mature enterocytes, like meprin A, SGLT1, and IFABp2, may be a direct result of this loss. In another part, replication of rotavirus in enterocytes imbedded in the epithelial layer could have down-regulated transcription of these genes. This may also be the case for other down-regulated genes from our list, especially for genes detected only at 18 hpi (R4-R13, Table 2 ). In addition to down-regulation of SGLT1, IFABp2, and meprin A, we observed up-regulation of two other genes that may affect the absorptive and digestive function of the intestine: a gene coding for a protein carrying a Ca 2+ -permeable cation channel CD20/IgE Fc receptor subunit b domain (MS4A2) and a gene homolog to a bacterial oligo/dipeptide permease (DppC-2). It is tempting to link up-regulation of MS4A2 directly to NSP4induced enhancement of Ca 2+ permeability of the plasma and ER membranes in intestinal epithelial cells [29, 40] . Likewise, up-regulation of the DppC-2 homolog may be related to enhanced laminal secretion of peptides and amines by uninfected epithelial cells, a process believed to be triggered by raised [Ca 2+ ] cyt [40] . Characterization of these porcine transcripts/proteins is needed to provide further insight in the role of these genes in rotavirus pathogenesis. The same applies for the TMEM106B gene. This gene showed the highest level of up-regulation. So far, only a DUF1356 protein domain with unknown function has been predicted in TMEM106B.