Search for the Function of NWC, Third Gene Within RAG Locus: Generation and Characterization of NWC-Deficient Mice

Abstract

NWC is a third gene within recombination activating gene (RAG) locus, which unlike RAG genes is ubiquitously expressed and encodes a unique protein containing three strongly evolutionarily conserved domains not found in any other known protein. To get insight into its function we identified several proteins co-immunoprecipitating with NWC protein and generated new NWC-deficient mice. Here, we present evidence that unlike many other ubiquitously expressed evolutionarily conserved proteins, functional inactivation of NWC does not cause any gross developmental, physiological or reproductive abnormalities and that under physiological conditions NWC may be involved in assembling and functioning of cilia, cell surface organelles found on nearly every eukaryotic cell.

Lack of NWC protein (c11orf74 homolog) in murine spermatogenesis results in reduced sperm competitiveness and impaired ability to fertilize egg cells in vitro

“…As previously described [15], using standard mating protocols we found no difference between WT and NWC-KO mice with regard to male and female fertility as assessed by the litter size. However, in the natural environment, females mate with multiple males, which leads to sperm competition.…”

“…Previously, we identified several proteins co-immunoprecipitaing with NWC from murine testis. Interestingly, most of those proteins are involved in intraflagellar transport (IFT) [15]. Therefore, it is possible that NWC mediates its cellular role through an interaction with one or more of those proteins.…”

“…The generation of NWC knock-out mice was described in a previous study, in which these mice were named NWC-KOMPcre [15]. However, in the present study, we refer to these mice as NWC-KO instead of NWC-KOMPcre for the sake of clarity.…”

“…NWC is transcribed in all tissues except mature lymphocytes [11–14]. However, the presence of the NWC protein in mice has been detected exclusively in the germinal layer in the testes [15]. The predicted structure of the NWC protein revealed three domains strongly conserved among vertebrates, two of which are also conserved in invertebrate species [16].…”

“…Although NWC is highly evolutionarily conserved, its cellular function remains unknown. The NWC-knockout (NWC-KOMPcre in [15]) mice revealed no apparent phenotype and are fertile in standard laboratory conditions. A histochemical analysis of testicular sections of these mice revealed the preservation of a layer of cells in the seminiferous tubules, and immunoprecipitation experiments showed that NWC interacts with proteins mostly involved in retrograde ciliary transport: IFT-139, IFT-144, IFT-122, IFT-43 and dynein light chain roadblock-type 1 [15].…”