Sperm-mediated DNA transfer to cells of the uterus and embryo

There is a paucity of information about sperm-mediated transmission of exogenous DNA to implanting embryos and cells of the reproductive tract. Preliminary experiments established that sperm has the capacity to actively take in exogenous DNA derived from HPV. In addition, blastocysts also take up exogenous HPV DNA, but in contrast to sperm, the process appears passive. DNA-carrying sperm migrating in an artificial glass tube or excised mouse bicornuate uteri transfected the blastocysts at the remote position using a flip-flop mechanism. There were preferential transmission of the types of HPV DNA but this was not attributed to the gene sequence or the size of the DNA fragments. The internalized DNA became undetectable unless continuous sperm bombardment or pricking took place. Mycoplasma vectors offer a novel way to enhance the transfection of blastocyst with exogenous DNA.