Disruption of the murine dynein light chain gene Tcte3-3 results in asthenozoospermia

Abstract

To elucidate the role of the mouse gene Tcte3 (Tctex2), which encodes a putative light chain of the outer dynein arm of cilia and sperm flagella, we have inactivated this gene in mice using targeted disruption. Breeding of heterozygous males and females resulted in normal litter size; however, we were not able to detect homozygous Tcte3-deficent mice using standard genotype techniques. In fact, our results indicate the presence of at least three highly similar copies of the Tcte3 gene (Tcte3-1, Tcte3-2, and Tcte3-3) in the murine genome. Therefore, quantitative real-time PCR was established to differentiate between mice having one or two targeted Tcte3-3 alleles. By this approach, Tcte3-3 K/K animals were identified, which were viable and revealed no obvious malformation. Interestingly, some homozygous Tcte3-3-deficient male mice bred with wild-type female produced no offspring while other Tcte3-3-deficient males revealed decreased sperm motility but were fertile. In infertile Tcte3-3 K/K males, spermatogenesis was affected and sperm motility was reduced, too, resulting in decreased ability of Tcte3-3-deficient spermatozoa to move from the uterus into the oviduct. Impaired flagellar motility is not correlated with any gross defects in the axonemal structure, since outer dynein arms are detectable in sperm of Tcte3-3 K/K males. However, in infertile males, deficient Tcte3-3 function is correlated with increased apoptosis during male germ cell development, resulting in a reduction of sperm number. Moreover, multiple malformations in developing haploid germ cells are present. Our results support a role of Tcte3-3 in generation of sperm motility as well as in male germ cell differentiation.

Disruption of murine Tcte3-3 induces tissue specific apoptosis via co-expression of Anxa5 and Pebp1

“…S2). Taken together, it is evident through restriction mapping that homologous recombination occurred in Tcte3-3 (Rashid et al, 2010).…”

“…Although Tcte3 is predominantly expressed in testis, its expression had also been monitored in several other tissues lacking cilia or flagella (DiBella et al, 2001;Neesen et al, 2002). Previously, we reported that at least three copies of Tcte3 exist in mouse genome and subsequent inactivation of Tcte3-3 copy results in sperm motility defects thereby resulting in partial male infertility phenotype (Rashid et al, 2010). Evidently, Tcte3-3 À/À testis exhibited an increased rate of apoptosis in spermiogenesis.…”

“…Tcte3-3 À/À mice (Rashid et al, 2010) were obtained from Institute of Human Genetics, Goettingen, Germany and kept at the animal facility of NCB, Quaid-i-Azam University (www.qau.edu. pk).…”

“…Previously, we reported that Tcte3-3 deficient mice bear defects in male fertility due to reduced sperm motility and a higher rate of apoptosis during spermatogenesis (Rashid et al, 2010). These mice were genotyped by real time PCR due to closer similarity in Tcte3 homologs.…”

“…Recently, it has been reported that dyneins have both direct and indirect roles in male germ cell apoptosis which results in male infertility phenotype (Rashid et al, 2010). Dynein is a large multi-subunit protein complex that powers minus end-directed movement along microtubules.…”