Gene Expression in Endocrine Tissues
(W501) DEVELOPMENTAL PATTERNS OF PPAR/RXR GENE EXPRESSION DURING SPERMATOGENESIS.
Thomas, Kelwyn1, Sung, Dae-Yong1, Chen, Xing1, Gibbs, Robert2, McCarrey, John3, Walker, William2, 1 Morehouse School of Medicine, Atlanta, GA2 University of Pittsburgh, Pittsburgh, PA3 University of Texas, San Antonio, TX
ABSTRACT- The nuclear receptor peroxisome proliferator receptors (PPARs) and retinoid X receptors (RXRs) are important mediators of selective gene activation during development and cellular differentiation. PPAR/RXR heterodimers bind to specific peroxisome proliferator responsive elements (PPREs) to transactivate the respective target genes. To investigate developmentally-specific patterns of expression of transcripts encoding the PPAR and RXR subunits, real-time RT PCR studies were performed using RNAs isolated from staput purified germ cells and prepuberal Sertoli cells. These studies indicate that transcripts encoding the PPAR , , and and RXR , , and are increasingly expressed in differentiating germ cells during spermatogenesis. The highest levels of expression for PPAR and RXR transcripts occurred in the preleptotene leptotene and zygotene spermatocytes. Significantly lower levels of PPAR and RXR expression were observed in developing prepuberal Sertoli cells, however, PPAR and RXR were expressed at the highest levels in 20 day Sertoli cell RNA samples. To determine whether the corresponding stage and cell-type-specific patterns are observed for the respective PPAR and RXR protein subunits, immunohistochemical studies are currently in progress on sections through the mouse seminiferous epithelium. These studies are supported by NIH grants U54HD41749, MBRS (GM08248) and RCMI (RRA 10303).
KEY WORDS: Testis, Spermatogenesis, Gene Expression