Total mouse genomic DNA was digested using EcoRI, BamHI, PstI, and XbaI. The digests were electrophoresed on a 1% agarose gel at 60V overnight and were transferred onto a Hybond N+ membrane from Amersham Pharmacia Biotech (Piscataway, NJ). A 32P-dATP labeled PCR fragment of the Mcoln1 coding region corresponding to exon 2 was used as a probe (primers 5'-CCCCACAGAAGAGGAAGAC-3' (forward) and 5'-AGATCTTGACCACCTGCAG-3' (reverse) with an annealing temperature of 59°C). Hybridization and washes were carried out in standard conditions [16].