pS2 gene especially expressed in the late G1/S phase of mouse astrocytes

By the reverse transcription-polymerase chain reaction we investigated the localization of pS2 mRNA, which encodes a secreted polypeptide of 60 amino acids with unknown function, in the adult mouse. This method revealed that the expression of pS2 mRNA was not restricted to the stomach as previously reported but was also found in various other tissues such as brain, heart, spleen, and muscle. The pS2 mRNA was additionally detected in astrocytes cultured from the whole brain of the newborn mouse. The pS2 expression in these astrocytes increased with cell growth and sharply declined after the cells reached the stationary phase. In the cells synchronized by the serum deprivation-refeeding technique, the expression of pS2 mRNA was only found at late G1 and S phase. These results suggest that the transcripts of pS2 gene are widely distributed throughout the entire body of the mouse and that they play some important cell cycle-related role in these tissues.