Moonshine illuminates a developmental role for regulated transcription elongation.

Mutations in the zebrafish gene moonshine, encoding the ortholog of TIF1 gamma, cause profound anemia and embryonic lethality. In a recent issue of Cell, Bai et al. provide evidence that these defects arise from inefficient transcription elongation, implicating elongation as an important point of regulation during cell differentiation and development. (c) 2010 Elsevier Inc. All rights reserved.