Protein Expression During Murine Thymus Differentiation

摘要

Driven by our long-standing interest in identifying proteins of the immune system and incharacterizing processes involved in lymphocyte differentiation, we studied protein expressionin biosynthetically labeled fetal and newborn thymus by 2D gel electrophoresis.Autoradiographs of the gels were scanned with a densitometer and image analysis wasperformed using theKeplersystem. Calibrated polypeptide spot abundances (volumes)were compared to assesses qualitative and quantitative changes of the spot volumes. Amongover 300 proteins evaluated at GD (gestation day) 13,15, and 17, there were sets of proteinsthat increased and others that decreased in intensity. We could in addition recognize proteinsthat were completely absent at GD 13 and/or 15 and that appeared thereafter togradually increase in intensity. Conversely, various polypeptide spots present at early stages(at GD 13 and 15) disappear later (at GD 17 or at birth). Among the proteins that increasein intensity prevail molecules with masses less than 35 kD, whereas a considerable portionof those that decrease in intensity are characterized by masses above 60 kD. Spots reportedin this communication were not defined beyond tagging them with numbers, which is aprerequisite to follow them up in the proteinpaedia developed in our laboratory. The nextstep will be to retrieve the coding sequences from the existing partitioned cDNA library(BW 5147) as well as from thymocyte subtraction libraries. We predict that among thosepolypeptides with varying intensity, important regulatory proteins in thymus developmentwill be found.