Gene transfer into the mammalian kidney: microtransplantation of retrovirus-transduced metanephric tissue.

Our previous observation that embryonic kidney tissue can develop and differentiate when transplanted into the parenchyma of mouse kidneys in the postnatal period provided an avenue for transferring novel genes into the mammalian kidney in vivo. Mouse metanephric tissue was infected ex vivo with a replication defective retrovirus which transduces the gene for beta-galactosidase. Seven to 21 days after transplantation of this tissue into neonatal and adult mouse kidneys, the expression of the gene, controlled by the viral long-terminal repeat promoter, was noted in approximately one-third of implants. Gene expression occurred predominantly in glomerular epithelial cells, but also in interstitial cells and in vascular structures. Polymerase chain reaction amplification of renal genomic DNA indicated the presence of viral DNA in 9 of 10 kidneys which had received metanephric implants into the neonatal renal cortex. These studies demonstrate the feasibility of short-term gene transfer into and expression within the mammalian kidney.