While many consider the structure of DNA to be well understood, this week a research group published solid evidence found for the first time in living cells a structure of DNA termed intercalated motif (I-motif). The I-motif is a four-stranded knot of looped DNA in which the cytosine nucleic acids bind each other instead of guanine. The researchers were able to identify this structure using custom monoclonal antibodies able to target the I-motif specifically within the living cell. Interestingly, the researchers also found the I-motif to be transitory in nature forming and deforming during the G1 phase of the cell cycle. As such they believe it may play a role in regulating DNA transcription.