IN-SITU LOCALIZATION WITH DIGOXIGENIN-LABELED PROBES OF TAU-RELATED MESSENGER-RNAS IN THE RAT PANCREAS

Two cDNA probes complementary to fetal rat brain tau cDNA were produce d by the polymerase chain reaction (PCR) and labelled by digoxigenin-1 1-dUTP incorporation during the PCR elongation step. These probes were tested for the in situ localization of tau mRNAs in sections of rat c erebellum. The hybridization signal was consistent with the known loca lization of brain tau mRNAs, showing the validity of cDNA probes label led by digoxigenin during the PCR. Using these probes, an in situ hybr idization protocol was established and optimized for the localization of tau-related mRNAs in sections of pancreas. The aim was to determine whether these mRNAs were expressed in the exocrine or the endocrine p art of the pancreas. A positive signal was found only in the exocrine part of the pancreas, and was distributed exclusively in the cytoplasm of acinar cells. The results described here are the first evidence fo r a specific expression of tau-related proteins in the exocrine pancre as.