Rat MDC family of proteins: Sequence analysis, tissue distribution, and expression in prepubertal and adult rat testis

Abstract

An increasing number of sequence‐related, cysteine‐rich membrane proteins containing metalloproteinase‐like and disintegrin‐like domains (the MDC protein family) have been identified in mammalian tissues. Here, we report the cloning and sequence analysis of cDNAs encoding several rat orthologues of this protein family, some of which are found to be expressed exclusively in the male reproductive tract, others exhibiting a broader tissue distribution. We also examine their expression in prepubertal and adult rat testis, which, in conjunction with the data on tissue distribution, form a necessary prelude to further studies aimed at establishing their individual functions. Mol. Reprod. Dev. 48:159–167, 1997. © 1997 Wiley‐Liss, Inc.

Chronological gene expression of ADAMs during testicular development: Prespermatogonia (gonocytes) express fertilin β (ADAM2)

“…The early developmental expression of fertilin ␣ (postnatal day 1 rat testis) was previously reported (Frayne et al, 1997). In contrast, the expression of fertilin ␤ mRNA was shown to occur by postnatal day 19 (Frayne et al, 1997), in correlation with the establishment of spermiogenesis (Wolfsberg et al, 1995). We have confirmed the identity of the cloned ADAM species by sequencing the RT-PCR products.…”

“…As a result, spermatogenic cell-specific fertilin ␣ and ␤ transcripts coexist 48 hr after birth. The early developmental expression of fertilin ␣ (postnatal day 1 rat testis) was previously reported (Frayne et al, 1997). In contrast, the expression of fertilin ␤ mRNA was shown to occur by postnatal day 19 (Frayne et al, 1997), in correlation with the establishment of spermiogenesis (Wolfsberg et al, 1995).…”

“…In contrast to ADAM6 and ADAM15, which are widely expressed (Frayne et al, 1997), both fertilin ␤ and cyritestin/ADAM3 are spermatogenic cell-specific (Heinlein et al, 1994), are expressed as a large precursor (Linder et al, 1995;Yuan et al, 1997), and each has a potential integrin ligand binding site in the disintegrin domain. Peptide mimetics as inhibitors and antibodies directed to active binding sites of fertilin ␤ and cyritestin/ADAM3 were shown to inhibit sperm-egg binding (Yuan et al, 1997;Linder and Heinlein, 1997).…”

“…The ␣ and ␤ subunits of the heterodimeric sperm protein fertilin (also designated ADAM-1 and ADAM-2, respectively; see http:// www.people.Virginia.edu/ϳjw7g/ Table_of_the_ADAMs.html for a table of ADAM gene and protein nomenclature) were the first members of the ADAM family to be recognized as spermatogenic cell-specific and implicated in sperm-egg membrane fusion (Primakoff et al, 1987). In addition to fertilin ␣ and fertilin ␤, the gene expression of several members of the ADAM family has been detected in somatic and spermatogenic cell components of prepubertal and adult rat testis and other organs (Frayne et al, 1997). An ␣6␤1 integrin receptor on mouse egg plasma membrane acts as the sperm receptor to which the disintegrin domain of fertilin ␤ binds (Almeida et al, 1995).…”

“…An earlier in situ hybridization study of guinea pig and mouse testis has determined that the expression of fertilin ␣ and ␤ transcripts begins during meiotic prophase, in pachytene spermatocytes. A more sensitive polymerase chain reaction (PCR) analysis of the developmental expression of the fertilin ␣ /␤ complex during rat spermatogenesis has revealed that fertilin ␣ is in fact detected from postnatal day 1 on, whereas fertilin ␤ expression is visualized from postnatal day 19 on (Frayne et al, 1997). This reported chronology suggests that the full assembly of the fertilin ␣/␤ heterodimer occurs after postnatal day 19.…”