Expression of a novel factor, short-type PB-cadherin, in Sertoli cells and spermatogenic stem cells of the neonatal rat testis

Abstract

In the rodent testis, contact-mediated interactions between gonocytes, or neonatal stem cells, and Sertoli cells are critical for development. Previously, we showed that the neural cell adhesion molecule (NCAM) serves as a Sertoli cell-gonocyte attachment factor in neonates. Its expression decreases dramatically by 1 week of age and eventually disappears in vivo, and appears to be downregulated by thyroid hormone (tri-iodothyronine (T 3 )). In this study, we used a cDNA microarray to screen for additional adhesion factors which might be important in testes of developing rats and detected expression of a novel factor, short-type PB-cadherin (STPB-C). Next, RT-PCR was used to generate cDNA for STPB-C from total RNA isolated from co-cultures, cDNA was cloned into pPCR-Script Amp SK(+) cloning vector, and plasmid DNA was isolated and sequenced to confirm the fidelity of the STPB-C cDNA portion of the plasmid. In situ hybridization analyses of testicular sections indicated that STPB-C expression in neonates is localized in the cytoplasm of many, but not all, gonocytes and in the cytoplasm of most of the surrounding Sertoli cells. Parallel hybridizations carried out on co-cultures also demonstrated a strong cytoplasmic signal in some gonocytes and in the great majority of the Sertoli cells of the underlying monolayer. With Northern analyses we found that STPB-C is expressed in vivo at high levels between days 1 and 5, with a subsequent large drop by day 10 and thereafter, suggesting that its expression may be associated with Sertoli or germ cell differentiation. Subsequent analyses of co-cultures exposed under a variety of conditions to T 3 suggest that, unlike NCAM, STPB-C is not regulated by this hormone. Next, we studied production of STPB-C protein by using an antiserum recognizing a peptide sequence unique to this factor in Western blotting and in immunolocalization. Signal was detected both intracellularly and at cell surfaces in most Sertoli cells and many gonocytes, although many of the latter cell type were also found to be negative for the protein, suggesting a potential role for STPB-C in survival and further development of some of these germ cells from which all subsequent spermatogenic cells originate.

Gonocytes, from the Fifties to the Present: Is There a Reason to Change the Name?1

“…Indeed, gonocytes were found to be associated to Sertoli cells via gap and desmosomelike junctions, believed to regulate communication between these cells [9]. A variety of cell adhesion molecules were found in gonocytes and Sertoli cells, including NCAM [10], PB-cadherin [11], and connexin 43 [12,13]. Thus, in order to migrate to the basement membrane, neonatal gonocytes need to free themselves from junctions with Sertoli cells and migrate between the lateral surfaces of adjacent Sertoli cells.…”

Differential gene expression in neural stem cells and oligodendrocyte precursor cells: A cDNA microarray analysis

“…Interestingly, several other surface antigens were found to be up-regulated in NSCs but not OPCs. Among them, P-selectin and short type PBcadherin are cell adhesion molecules (Edwards et al, 2000;Wu et al, 2003). These molecules, expressed on NSCs, may be involved in the morphogenesis of these cells to maintain neurosphere aggregation.…”

Over-Expression of CDH22 Is Associated with Tumor Progression in Colorectal Cancer

“…It has been shown previously that CDH22 is involved in morphogenesis and tissue formation in the neural and nonneural cells of the brain and neuroendocrine organs [9] . Over-expression of CDH22 can increase survival or production of gonocytes in testis of neonatal rats [10] .…”