Pancreatic lipase-related protein 1 mRNA in female mouse lacrimal gland

PURPOSE. Differential display analysis was used to look for gender differen ces in lacrimal gland gene expression The expression of a female-specific m ouse lacrimal gland mRNA that encoded pancreatic lipase-related protein I ( PLRP1) was identified and characterized. METHODS. Differential display analysis of the exorbital lacrimal glands of male and female Swiss Webster mice detected a potential female-specific cDN A, designated Y2. Using the technique of rapid amplification of cDNA ends, a full-length cDNA of Y2 was obtained and the nucleotide sequence determine d. To assess tissue-specific expression, a labeled Y2 cDNA probe was hybrid ized to RNA blots of male and female mouse lacrimal, harderian, parotid, ma ndibular, sublingual, and pancreas glands and liver. Y2 cDNA was also hybri dized to RNA blots of male and female rat lacrimal gland and male rat pancr eas. To determine subcellular localization, Y2 sense and antisense RNA prob es were hybridized to female mouse lacrimal gland frozen sections. RESULTS. GenBank database sequence comparisons indicated that Y2 encoded mo use PLRP1. RNA blots documented that PLRP1 was expressed in female, but not in male, mouse lacrimal gland. PLRP1 mRNA was also expressed in male and f emale mouse sublingual gland and pancreas. Expression of PLRP1 was not dete cted in male or female rat lacrimal gland. In situ hybridization showed tha t PLRP1 was expressed in the acinar cells of the female mouse lacrimal glan d. CONCLUSIONS. Lacrimal gland expression of PLRP1 mRNA was gender and species specific. Female, but not male, mouse lacrimal gland expressed PLRP1 mRNA. Neither female nor male rat lacrimal gland expressed PLRP1 mRNA. PLRP1 pro tein may be secreted in mouse tears, where it may function as a lipolytic e nzyme, modifying tear Nm lipids.