Human CRYL1, a novel enzyme-crystallin overexpressed in liver and kidney and downregulated in 58% of liver cancer tissues from 60 Chinese patients, and four new homologs from other mammalians.

Lambda-crystallin is a composition of lens in rabbit and hare. It contains the putative NAD- or FAD-binding domain, which is named as HCDH domain in 3-hydroxyacyl-CoA dehydrogenase. In our attempt to search for genes differentially expressed between liver cancer tissues and normal tissues, human CRYL1 (crystallin, lambda 1) was identified. It was downregulated in 58% of 60 Chinese HCC tissue samples. The putative protein encoded by CRYL1 shares 83% identity with rabbit lambda-crystallin and contains two HCDH domains. Interestingly, CRYL1 mRNA level is remarkably high in liver and kidney, while it is extremely low in peripheral blood leukocyte and thymus. The CRYL1mRNA levels in liver and kidney are about 1.6 and 1.2 times the total amount of that in other 14 tissues, respectively. Both the special expression pattern and the putative HCDH structure of CRYL1 suggested that the protein may be of the similar function of 3-hydroxyacyl-CoA dehydrogenase. To further understand the lambda-crystallin protein family, we cloned four novel mammalian homologs from mouse, rat, bovine and pig. The unrooted phylogenetic tree of this protein family including human and other 26 species was drawn to analyse their evolutionary relationship. In addition, human CRYL1 was mapped to chromosome 13q12.11 and mouse Cryl1 to chromosome 14 between marker D14Mit83 and D14Mit260.