Prostate stem cell antigen gene is expressed in islets of pancreas / 대한해부학회지

Prostate stem cell antigen (PSCA) is a glycosylphosphatidylinositol-anchored cell surface antigen with an organ-dependent expression pattern in cancers; e.g., up-regulated in prostate cancer and down-regulated in gastric cancer. Previously it was reported that PSCA is not expressed in the normal pancreas but aberrantly expressed in pancreatic cancer. In this present study, we identified PSCA expression in islets of the pancreas by immunohistochemistry, which was co-localized with four islet-cell markers: insulin, glucagon, somatostatin and pancreatic polypeptide. In our investigation of the transcription start site of PSCA, we found a non-coding splicing variant of PSCA as well as authentic PSCA transcripts in mRNA samples from a normal pancreas. Both the transcripts were also identified in several pancreatic cancer cell lines. We previously reported that PSCA expression is correlated to the methylation status of the enhancer region in gastric and gallbladder cancer cell lines but not in pancreatic cancer cell lines, suggesting that PSCA expression is regulated in a diff erent mode in pancreatic cancer from that in gastric and gallbladder cancers.

New Splicing Variants of the Murine Damaged DNA Binding 2 / 한국실험동물학회지

Damaged DNA binding (DDB) protein is an important gene in the repair of damaged DNA. DDB is a heterodimer (DDB1 and DDB2) protein, murine DDB2 has 10 exons about 1.5kb in size (Genbank Accession No. AY027937). Here we identified five DDB2 variants (M1-M5) from various mouse tissues that are generated by alternative splicing. We used reverse transcription-PCR (RT-PCR) to identify splicing variants and isolated PCR products using an agarose-gel PCR purification kit. All isolated PCR products were cloned and the structure of splicing variants was confirmed by sequencing. The first splicing variant M1 was generated by omission of exon 4. The second splicing variant M2, by omission of exons 4-5. The third variants M3 was generated by omission from the middle of exon 1 to exon 6 and was expressed in the heart. Fourth variants M4 was generated by omission of exon 2 and exons 4-7. M5, the last splicing variant was generated by omission of exons 4-7. M4 and M5 were expressed in the spleen. Analysis of tissue distribution by RT-PCR indicates that M1 is most highly expressed in the mouse brain. These results indicated that murine DDB2 has five splicing variants and splicing variants expression patterns were different depending on mouse tissue. Further functional studies of each splicing variants will provide more information about the molecular mechanism of DDB2 function and DDB2 gene expression regulation.