Cryptic Transcription and Early Termination in the Control of Gene Expression

Figure 1

Complexity of the transcriptional landscape in yeast. Transcription of genes encoding stable RNAs by RNAP II is indicated by black lines and cryptic transcription originated from 5′ and 3′ nucleosome free regions (NFRs) is depicted in red. Initiation of transcription is represented by bent arrows and nucleosomes are depicted by grey ovals. Transcription can lead to the production of polyadenylated mRNAs that are competent for export to the cytoplasm and subsequent translation. Initiation of cryptic transcription is minimized by chromatin modifying and remodelling complexes (CMRs) that impose a repressive structure on the chromatin. When those mechanisms are insufficient, the Nrd1 complex terminates transcription and recruits the TRAMP and exosome complexes, which leads to polyadenylation and degradation of the generated CUT.