Lentiviral vector transduction of spermatozoa as a tool for the study of early development

Intratesticular injection followed by electroporation allows gene transfer in caprine spermatogenic cells

The production of transgenic livestock is constrained due to the limited success of currently available methods for transgenesis. Testis mediated gene transfer (TMGT) is an emerging method that shows a high success rate in generating transgenic mice. In this study, we report a newly developed protocol for electroporation-aided TMGT to produce a transgenic goat. The injectable volume and concentration of the transgene were first standardized, and then electroporation conditions were optimized in vitro. In vivo experiments were performed by injecting a transgenic construct (pIRES2-EGFP; enhanced green fluorescent protein) into the testicular interstitium followed by electroporation. Immunohistochemistry, quantitative real-time PCR (qPCR) and western blotting analyses confirmed the successful transfer of the transgene into seminiferous tubules and testicular cells. Furthermore, chromosomal integration of the transgene and its expression in sperm were evaluated d60 and d120 post-electroporation. Our protocol neither altered the seminal characteristics nor the fertilization capacity of the sperm cells. In vitro fertilization using transgenic sperm generated fluorescent embryos. Finally, natural mating of a pre-founder buck produced a transgenic baby goat. The present study demonstrates the first successful report of an electroporation-aided TMGT method for gene transfer in goats.

Generating Transgenic Mice by Lentiviral Transduction of Spermatozoa Followed by In Vitro Fertilization and Embryo Transfer

Most transgenic technologies rely on the oocyte as a substrate for genetic modification. Transgenics animals are usually generated by the injection of the gene constructs (including lentiviruses encoding gene constructs or modified embryonic stem cells) into the pronucleus of a fertilized egg followed by the transfer of the injected embryos into the uterus of a foster mother. Male germ cells also have potential as templates for transgenic development. We have previously shown that mature sperm can be utilized as template for lentiviral transduction and as such used to generate transgenic mice efficiently with germ line capabilities. We provide here a detailed protocol that is relatively simple, to establish transgenic mice using lentivirally transduced spermatozoa. This protocol employs a well-established lentiviral gene delivery system (usual for somatic cells) delivering a variety of transgenes to be directly used with sperm, and the subsequent use of these modified sperm in in vitro fertilization studies and embryo transfer into foster female mice, for the establishment of transgenic mice.

Bioimaging of microRNA34c in a single sperm using a molecular beacon

The VisuFect-conjugated molecular beacon was developed for non-invasive visualization of microRNA34c in a living single mouse sperm.

Regulation and roles of Ca2+ stores in human sperm

[Ca(2)(+)]i signalling is a key regulatory mechanism in sperm function. In mammalian sperm the Ca(2)(+)-permeable plasma membrane ion channel CatSper is central to [Ca(2)(+)]i signalling, but there is good evidence that Ca(2)(+) stored in intracellular organelles is also functionally important. Here we briefly review the current understanding of the diversity of Ca(2)(+) stores and the mechanisms for the regulation of their activity. We then consider the evidence for the involvement of these stores in [Ca(2)(+)]i signalling in mammalian (primarily human) sperm, the agonists that may activate these stores and their role in control of sperm function. Finally we consider the evidence that membrane Ca(2)(+) channels and stored Ca(2)(+) may play discrete roles in the regulation of sperm activities and propose a mechanism by which these different components of the sperm Ca(2)(+)-signalling apparatus may interact to generate complex and spatially diverse [Ca(2)(+)]i signals.