An RNA first: it's part of the gene-copying machinery.
Hoffman
M
M
D000818:Animals; D012831:Bombyx / Q000235:genetics*; D004247:DNA / Q000235:genetics; D012313:RNA / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism*
D014157:Transcription Factors; D012313:RNA; D004247:DNA