This family consists of several Zea mays specific MURB-like proteins. The transposition of Mu elements underlying Mutator activity in maize requires a transcriptionally active MuDR element. Despite variation in MuDR copy number and RNA levels in Mutator lines, transposition events are consistently late in plant development, and Mu excision frequencies are similar [1].

1: Expression and post-transcriptional regulation of maize transposable element MuDR and its derivatives. Rudenko GN, Walbot V; Plant Cell 2001;13:553-570. PMID:11251096