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. Author manuscript; available in PMC: 2013 May 2.
Published in final edited form as: Science. 2012 Sep 27;338(6107):671–675. doi: 10.1126/science.1224350

Figure 4. Gene loop disruption by PAS mutation enhances divergent transcription.

Figure 4

A-C) I. Graphical representation of 3C interaction analyses for CYC1 plasmid (A), MSN5 (B) and mammalian β-globin gene construct (C) as in Fig. 1A. II, RT-qPCR analyses of mRNA versus pncRNAs. AIII. Northern blot for CYC1 transcripts. Note that the CYC1 mRNA is smaller with RCS replacement due to lack of pA tail. Also UTR1 downstream of CYC1 is inactive due to promoter deletion, denoted by crossed arrow. Error bars represent SEM. D) Gene loop defines transcription unit and promotes transcription directionality. Loss of gene loop in ssu72-2 or with PAS mutation increases antisense pncRNA transcription. Gene loops involving Ssu72 (green oval) may act to maintain nucleosome (yellow bubble; ac denotes H4Ac) positions, preventing association of a second PIC (red) leading to divergent transcription initiation.