Researchers have improved the success rate for producing cloned embryos or embryonic stem cells by removing a chemical group from DNA-binding proteins.

Transferring a nucleus from an individual's adult body cell into a human egg — a process called somatic cell nuclear transfer (SCNT) — could one day generate embryonic stem cells that match that person's DNA. But embryos made using SCNT rarely mature. To improve this, Dong Ryul Lee at CHA University in Seoul, Yi Zhang at Boston Children's Hospital in Massachusetts and their colleagues used a human messenger RNA encoding a protein that removes methyl groups from a type of histone protein found on DNA in the donor nucleus. When the authors injected the RNA into 56 human eggs that had received donor DNA, they found that 14.3% of the treated embryos developed into late-stage blastocysts, compared with none of the untreated controls.

Using this technique, the team derived embryonic stem cells from skin cells donated by people with age-related macular degeneration, which causes partial vision loss.

Cell Stem Cell http://doi.org/8v2 (2015)