Gene loops have been described in different organisms from yeast to human and form through interaction between components of the transcription pre-initiation complex and Ssu72, a member of the 3′ end cleavage and polyadenylation complex. A recent study by Tan-Wong et al. reports a new role for gene loops in promoting ORF transcription directionality from otherwise bidirectional promoters.
SM Tan-Wong, JB Zaugg, J Camblong, Z Xu, DW Zhang, HE Mischo, AZ Ansari, NM Luscombe, LM Steinmetz, NJ Proudfoot. Gene loops enhance transcriptional directionality. Science 2012; 338: 671- 5.
PMID: 23019609 DOI: 10.1126/science.1224350