The hyaluronidase gene HYAL1 maps to chromosome 3p21.2-p21.3 in human and 9F1-F2 in mouse, a conserved candidate tumor suppressor locus.

We recently cloned and expressed the major hyaluronidase activity from human plasma, HYAL1, and found that the protein is 40% identical to the testicular hyaluronidase, PH-20. The HYAL1 mRNA sequence was used in a homology search of the mouse database of expressed sequence tags (dbEST). Two ESTs were obtained and, in combination with 5'RACE-PCR, were used to clone the mouse HYAL1 ortholog (Hyal1). Hyal1 codes for a protein of 462 amino acids that is 73% identical to the human sequence. Hyal1 stably expressed in human embryonic kidney cells resulted in a 20,000-fold increase of hyaluronidase activity. Sequence-tagged sites derived from the HYAL1 gene from both species were used to isolate P1 genomic clones that were used as probes for fluorescence in situ hybridization. The human gene was localized to chromosome 3p21 and the mouse gene to a syntenic region on chromosome 9F1-F2. In mouse, serum hyaluronidase polymorphism has previously been mapped by an interspecific backcross to 60 cM from the centromere of chromosome 9, which corresponds to a cytogenetic location of 9F1-F2. The mouse Hyal1 gene is therefore very likely to be responsible for the hyaluronidase polymorphism linked to this locus. We also present evidence that human HYAL1 is identical to an uncharacterized gene positionally cloned by others from chromosome 3p21.3 that is homozygously deleted in several small-cell lung carcinoma cell lines.