The Escherichia coli RNA polymerase α subunit linker: length requirements for transcription activation at CRP‐dependent promoters Comparison of the effect of deletions and insertions within the α inter‐domain linker on transcription from CRP‐dependent promoters in vitro and in vivo. (A) Amount of transcripts produced by RNAP reconstituted with each mutant α subunit in the presence of CRP at the CC(−41.5) (▴) and CC(−61.5) (○) promoters in vitro. Data are taken from Figure 3. (B) Activity of the CC(−41.5) (▴) and CC(−61.5) (○) promoters in cells expressing chromosome‐encoded wild‐type α and plasmid‐encoded mutant or wild‐type α. Data are taken from Figure 8. Values in both panels are expressed as a percentage of the promoter activity in the presence of RNAP containing only wild‐type α. IF THIS IMAGE HAS BEEN PROVIDED BY OR IS OWNED BY A THIRD PARTY, AS INDICATED IN THE CAPTION LINE, THEN FURTHER PERMISSION MAY BE NEEDED BEFORE ANY FURTHER USE. PLEASE CONTACT WILEY'S PERMISSIONS DEPARTMENT ON PERMISSIONS@WILEY.COM OR USE THE RIGHTSLINK SERVICE BY CLICKING ON THE 'REQUEST PERMISSIONS' LINK ACCOMPANYING THIS ARTICLE. WILEY OR AUTHOR OWNED IMAGES MAY BE USED FOR NON-COMMERCIAL PURPOSES, SUBJECT TO PROPER CITATION OF THE ARTICLE, AUTHOR, AND PUBLISHER. EMBO J, Volume: 19, Issue: 7, Pages: 1555-1566, First published: 03 April 2000, DOI: (10.1093/emboj/19.7.1555)