3-Methyl-3-deazaadenine, a stable isostere of N3-methyl-adenine, is efficiently bypassed by replication in vivo and by transcription in vitro

► The effects on DNA metabolism of a stable isostere of 3methyladenine, 3-methyl-3-deazaadenine (3-m-c3A), are presented. ► 3-m-c3A was site specifically positioned, and incorporated into a vector system that is converted to ssDNA inside yeast cells. ► 3-m-c3A does not significantly affect neither DNA replication in vivo nor RNA transcription in vitro. ► Considering bypass events opposite 3-m-c3A the absence of Polη was associated with an increase in AT>GC transitions.