Next, we directly compared the nucleotide and amino acid sequence of the alternatively spliced mouse transcript to the entire human MCOLN1 genomic sequence and found no significant similarity. As mentioned previously, Northern blots performed with human MCOLN1 probes show only one 2.4 kb transcript. In addition, we hybridized a human multiple tissue Northern and human Southern with a probe in human intron 12 that is adjacent to exon 13. The probe was located in the region syntenic to that which encodes the alternate mouse transcript. Only the expected bands were detected on the Southern and no bands were detected on the Northern, confirming that this alternative transcript is specific to murine Mcoln1. Recent BLASTP analysis of the alternate Mcoln1 transcript yields a match to a putative 145 amino acid anonymous protein (GB No. BAB25862) predicted from a RIKEN clone. It is obvious from our results, however, that the identification of this sequence as a full-length protein is incorrect since probes unique to the clone, as well as probes containing the Mcoln1 coding sequence, identify the same transcripts.