IDENTIFICATION OF CIRCADIAN GENE-EXPRESSION IN THE RAT PINEAL-GLAND AND RETINA BY MESSENGER-RNA DIFFERENTIAL DISPLAY

To identify unique gene products that could be crucial for circadian a nd light-dark regulations, using the technology of differential displa y, we have investigated mRNAs that were isolated from rat pineals and retinas collected either during subjective day (D) or subjective night (N). A subpopulation of about 50 mRNAs were amplified from pineal usi ng designed primers and reverse transcriptase-polymerase chain reactio n. Thirty five of the mRNAs were expressed equivalently in both D and N samples. From the 15 mRNAs showing differential expression, four amp lified products were selected, based on higher expression during the s ubjective night (N310, N320, N383, N420) and each was subcloned and se quenced. Of the four cDNAs studied, only N310 was determined to have s ignificant identity to a known cell adhesion protein, called F3. This protein is highly expressed in developing mouse neurons and is related to chicken contactin. Each differentially displayed product identifie d is being examined further in order to understand their potential sig nificance in the circadian regulation of pineal and retinal activities .