A COMPREHENSIVE SURVEY OF THE CADHERINS EXPRESSED IN THE TESTES OF FETAL, IMMATURE, AND ADULT MICE UTILIZING THE POLYMERASE CHAIN-REACTION

The cadherins are a family of calcium-binding membrane glycoproteins. Most cadherins are capable of acting as cell adhesion molecules (CAMs) . In order to begin a thorough analysis of the roles of these CAMs in the testis, we employed a reverse transcriptase-polymerase chain react ion (RT-PCR) strategy to identify the cadherins expressed in this tiss ue at various stages of development. Oligonucleotides encoding amino a cid sequences that are conserved among all of the known cadherins were used as primers in the RT-PCR, with cDNA preparations of fetal, newbo rn, 7-day, 21-day, and adult mouse testes employed as templates. The P CR products were subcloned into a plasmid vector and sequenced. On the basis of the nucleotide sequences of these PCR products, we have dete rmined that five previously characterized cadherins (E-cadherin, N-cad herin, P-cadherin, K-cadherin, and OB-cadherin), as well as two novel cadherins (T1-cadherin and T2-cadherin), are expressed at various stag es during testicular development. In order to determine the expression patterns of these cadherins, we ascertained the mRNA levels of each c adherin normalized to the levels of hypoxanthine phosphoribosyltransfe rase mRNA in fetal, newborn, 7-day, 21-day, and adult mouse testes. We observed that N-cadherin mRNA is expressed at all stages of testicula r development, with maximal levels being present in the testes of 21-d ay-old mice. Furthermore, we found that E-, P-, K-, OB-, and T2-cadher in mRNAs are all expressed in the fetal gonad. The testicular levels o f these cadherin mRNAs decreased dramatically after birth. Conversely, T1-cadherin mRNA was not detected in the fetal, newborn, and 7-day-ol d testes but was present in 21-day-old and adult testes. T1-cadherin l evels were 10-fold higher in the testes of adult mice, compared to the levels found in the testes of 21-day-old mice. We speculate that thes e cadherins will be found to be intimately involved in mediating cell interactions during testicular development.