id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-297078-pxggjaby	Poole, Anthony M.	Modern mRNA Proofreading and Repair: Clues that the Last Universal Common Ancestor Possessed an RNA Genome?	2005-03-16		.txt	text/plain	8279	391	50	Leipe, Aravind, and Koonin (1999) suggest that LUCA possessed a hybrid DNA/RNA genome, thereby providing an explanation for the universal distribution of certain components of the DNA replication/repair apparatus. We argue from structural and functional data that the second of these, RNA polymerase-dependent proofreading and repair, is likely to have been a feature of LUCA rather than a recent innovation as part of selection for improved messenger RNA (mRNA) quality control, though this is no doubt the current function of this phenomenon. In this scenario, cleavage-stimulatory factors evolved twice independently (GreA/GreB in bacteria and transcription factor S/TFIIS in archaea/eukaryotes) with an initial function in RNA genome repair. This implies that the LUCA possessed an RNA genome, and in this scenario, bacterial RNA polymerase-associated cleavage-stimulatory factors (GreA/GreB) and their archaeal/eukaryotic equivalents (TFS/TFIIS) were originally involved in proofreading and repair of the genome, as indicated by [Gen] .	./cache/cord-297078-pxggjaby.txt	./txt/cord-297078-pxggjaby.txt