Cover image

In this issue, Moyers et al. report on analyses of 680 transcription factors in the HepG2 cell line. Transcription factors are depicted as characters associated with DNA, regulating the expression of genes. Some carry flags, denoting tagged ChIP-seq experiments. Some associate with one another by holding hands where different regions of DNA loop together, interacting to achieve the connection between the two distal DNA strands. Some characters accumulate in large numbers, depicting High Occupancy Target (HOT) sites on the DNA. A repressive transcription factor character flexes its muscles to keep others away. Histone proteins are larger characters around which DNA wraps. (Cover illustration concept by Cathleen Shaw, cshaw@hudsonalpha.org. [For details, see Moyers et al., pp. 1879–1892.])