RNA "lixo": de mensageiro a guardião da integridade genômica - mero acaso, fortuita necessidade ou design inteligente???

quinta-feira, maio 24, 2012

A cada pesquisa em biologia, os cientistas cada vez mais descobrem complexidade em cima de complexidade e, pior para os evolucionistas, cada vez mais descobrem teleologia, reforçando assim a teoria do Design Inteligente.

Dê uma olhada nesta pesquisa sobre certas regiões não codificantes do RNA, publicada na Nature. A linguagem do Abstract dos autores é teleológica. E dizem por aí os iluminados que Darwin eliminou a teleologia da Biologia. NADA MAIS FALSO!!!


“RNA: From Messenger to Guardian of Genome Integrity” (ScienceDaily, May 23, 2012), nós somos informados:

"For decades the scientific community has attributed a role to RNA that is subordinate to that of DNA: the functional processes of expression of genetic information into proteins. With some known exceptions, such as the classes of tRNA and rRNA involved in the synthesis of proteins, RNA molecules were considered “fleeting” messengers necessary to carry genetic instructions from the nucleus, site of the genome, to the cytoplasm where proteins, the scaffolding of living organisms, are produced.

In recent years, this simplistic view has given way to an increasingly complex scenario, with the identification of new RNA classes involved in numerous cellular events.

One in particular, however, had never been identified or described to date: it is DDRNA, a class of non protein-coding RNAs that are generated every time the genome is damaged. They originate from the same sequence of DNA damaged and have the essential task of launching the molecular alarms through which the cell detects the problem and resolves it by repairing the damage."


Site-specific DICER and DROSHA RNA products control the DNA-damage response

Sofia Francia, Flavia Michelini, Alka Saxena, Dave Tang, Michiel de Hoon, Viviana Anelli, Marina Mione, Piero Carninci & Fabrizio d’Adda di Fagagna

Nature (2012) doi:10.1038/nature11179

Received 08 February 2010 
Accepted 04 May 2012 
Published online 23 May 2012


Non-coding RNAs (ncRNAs) are involved in an increasingly recognized number of cellular events1. Some ncRNAs are processed by DICER and DROSHA RNases to give rise to small double-stranded RNAs involved in RNA interference (RNAi)2. The DNA-damage response (DDR) is a signalling pathway that originates from a DNA lesion and arrests cell proliferation3. So far, DICER and DROSHA RNA products have not been reported to control DDR activation. Here we show, in human, mouse and zebrafish, that DICER and DROSHA, but not downstream elements of the RNAi pathway, are necessary to activate the DDR upon exogenous DNA damage and oncogene-induced genotoxic stress, as studied by DDR foci formation and by checkpoint assays. DDR foci are sensitive to RNase A treatment, and DICER- and DROSHA-dependent RNA products are required to restore DDR foci in RNase-A-treated cells. Through RNA deep sequencing and the study of DDR activation at a single inducible DNA double-strand break, we demonstrate that DDR foci formation requires site-specific DICER- and DROSHA-dependent small RNAs, named DDRNAs, which act in a MRE11–RAD50–NBS1-complex-dependent manner (MRE11 also known as MRE11A; NBS1 also known as NBN). DDRNAs, either chemically synthesized or in vitro generated by DICER cleavage, are sufficient to restore the DDR in RNase-A-treated cells, also in the absence of other cellular RNAs. Our results describe an unanticipated direct role of a novel class of ncRNAs in the control of DDR activation at sites of DNA damage.

Source/Fonte: Nature

100% Design Inteligente!!!


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