Production of Transgenic F0 Animals and Permanent Lines by Sperm Nuclear Transplantation in Xenopus tropicalis

Abstract
Early efforts in the 1980s showed that DNA microinjected into Xenopus embryos could be integrated into the genome and transmitted through the germline at low efficiency. Subsequent studies revealed that transgenic lines, typically with multiple-copy inserts (e.g., to develop bright fluorescent protein-reporter lines), could be created via sperm nuclear injection protocols such as the one entitled restriction enzyme-mediated insertion, or REMI. 

Takuya Nakayama, Jessica Gray, Robert M Grainger
https://pubmed.ncbi.nlm.nih.gov/36283835/