Molecular Cloning and Characterization of CD9 cDNA from Sheep and Cashmere Goat

Expression of CD9 on porcine lymphocytes and its relation to T cell differentiation and cytokine production

In this work, we report on two novel monoclonal antibodies, specific for porcine CD9. CD9 is a tetraspanin that is expressed on a wide variety of cells. We phenotyped porcine immune cell subsets and found that CD9 was expressed on all monocytes as well as a subset of B cells. CD9 was variably expressed on T cells, with CD4 T cells containing the highest frequency of CD9⁺ cells. CD9 expression positively correlated with the frequency of central memory CD4 T cells in ex vivo PBMC. Therefore, we proceeded to explore CD9 as a marker of T cell function. Here we observed that CD9 was expressed on the vast majority of long-lived influenza A virus-specific effector cells that retained the capacity for cytokine production in response to in vitro recall antigen. Therefore, the new antibodies enable the detection of a cell surface molecule with functional relevance to T cells. Considering the importance of CD9 in membrane remodelling across many cell types, they will also benefit the wider field of swine biomedical research.

CD9, a tetraspanin target for cancer therapy?

In the present minireview, we intend to provide a brief history of the field of CD9 involvement in oncogenesis and in the metastatic process of cancer, considering its potential value as a tumor-associated antigenic target. Over the years, CD9 has been identified as a favorable prognostic marker or predictor of metastatic potential depending on the cancer type. To understand its implications in cancer beside its use as an antigenic biomarker, it is essential to know its physiological functions, including its molecular partners in a given cell system. Moreover, the discovery that CD9 is one of the most specific and broadly expressed markers of extracellular membrane vesicles, nanometer-sized entities that are released into extracellular space and various physiological body fluids and play a role in intercellular communication under physiological and pathological conditions, notably the establishment of cancer metastases, has added a new dimension to our knowledge of CD9 function in cancer. Here, we will discuss these issues as well as the possible cancer therapeutic implications of CD9, their limitations, and pitfalls.

The molecular mechanisms mediating mammalian fertilization

Fertilization is a key biological process in which the egg and sperm must recognize one another and fuse to form a zygote. Although the process is a continuum, mammalian fertilization has been studied as a sequence of steps: sperm bind and penetrate through the zona pellucida of the egg, adhere to the egg plasma membrane and finally fuse with the egg. Following fusion, effective blocks to polyspermy ensure monospermic fertilization. Here, we review how recent advances obtained using genetically modified mouse lines bring new insights into the molecular mechanisms regulating mammalian fertilization. We discuss models for these processes and we include studies showing that these mechanisms may be conserved across different mammalian species.

Involvement of tetraspanin 8 in the innate immune response of the giant prawn, Macrobrachium rosenbergii

The tetraspanins, representing a conserved superfamily of four-span membrane proteins, are highly involved in viral and bacterial infections. Thus far, the function of the tetraspanins in crustaceans remains largely unknown. In this study, we report the cloning and expression analysis of a tetraspanin 8 from the giant freshwater prawn, Macrobrachium rosenbergii (named as MrTspan8). MrTspan8 contains a 720-bp open reading frame encoding a 239-amino acids protein, which exhibits four transmembrane domains and two extracellular loops that are typical for tetraspanins. MrTspan8 was found to be widely expressed in a variety of prawn tissues including heart, gill, muscle, gut, and hepatopancreas. Additionally, MrTspan8 expression was significantly increased in the hepatopancreas and gill of the prawns challenged by the bacterial pathogen Aeromonas hydrophila. Moreover, we show that pre-incubation of the peptides from the large extracellular loop of MrTSPAN8 protein reduced the cell death caused by A. hydrophila infection in prawn tissue, suggesting that MrTSPAN8 could be a mediator for bacterial infection to prawn.

Molecular cloning of sheep and cashmere goat Pdia3 and localization in sheep testis

Protein disulphide isomerase family A3 (PDIA3) is a member of the protein disulphide isomerase (PDI) family and is multifunctional in many processes. Recently, it has been confirmed as a sperm membrane component and is implicated in sperm-egg fusion under which the molecular mechanism is still obscure. Protein disulphide isomerase family A3 cDNA has been cloned in several mammals; however, goat and sheep counterparts have not been identified. To facilitate the studies on the potential function of PDIA3 protein in sperm-egg fusion in sheep and goat, we cloned the cDNA encoding for Pdia3 of sheep (Ovis aries) and cashmere goat (Capra hircus) and studied its transcript and protein localization in sheep testis. The cloned sheep and cashmere goat Pdia3 cDNA are 1660 bp and 1591 bp, respectively. Bioinformatics analysis showed that sheep and goat Pdia3 cDNA both have a coding region of 1518 bp with the same nucleotides encoding the same 505 amino acids. The predicted peptide, with two typical motifs of Trp-Cys-Gly-His-Cys-Lys (WCGHCK) which is a hallmark of the PDI family, has high homology to that of bovine (99.21%), human (95.05%), rat (89.50%) and mouse (90.89%). Protein disulphide isomerase family A3 protein was observed in cells of various stages of spermatogenesis, from the primary spermatocyte to spermatozoa phases, as well as in the Leydig cells. It was observed in the entire sheep spermatozoa and mostly at the equatorial segment and the forepart of the flagellum. The Pdia3 mRNA was detected over the seminiferous epithelium in all stages of spermatogenesis.