Active RNA polymerases: mobile or immobile molecular machines?
It is widely assumed that active RNA polymerases track along their templates to produce a transcript. We test this using chromosome conformation capture and human genes switched on rapidly and synchronously by tumour necrosis factor alpha (TNFalpha); one is 221 kbp SAMD4A, which a polymerase takes more than 1 h to transcribe. Ten minutes after stimulation, the SAMD4A promoter comes together with other TNFalpha-responsive promoters. Subsequently, these contacts are lost as new downstream ones appear; contacts are invariably between sequences being transcribed. Super-resolution microscopy confirms that nascent transcripts (detected by RNA fluorescence in situ hybridization) co-localize at relevant times. Results are consistent with an alternative view of transcription: polymerases fixed in factories reel in their respective templates, so different parts of the templates transiently lie together.
Papantonis
Argyris
A
Sir William Dunn School of Pathology, Medical Sciences Division, University of Oxford, Oxford, United Kingdom.
Larkin
Joshua D
JD
Wada
Youichiro
Y
Ohta
Yoshihiro
Y
Ihara
Sigeo
S
Kodama
Tatsuhiko
T
Cook
Peter R
PR
D020029:Base Pairing / Q000235:genetics; D002478:Cells, Cultured; D002883:Chromosomes, Human, Pair 14 / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007438:Introns / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D034443:RNA Transport / Q000187:drug effects; D012097:Repressor Proteins / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D012097:Repressor Proteins; C507993:SAMD4A protein, human; D014409:Tumor Necrosis Factor-alpha; D012321:DNA-Directed RNA Polymerases