نتایج جستجو برای: mirnas biogenesis
تعداد نتایج: 40763 فیلتر نتایج به سال:
MicroRNAs (miRNAs) are small regulatory RNAs that are involved in many biological process in eukaryotes. They play a crucial role in modulating genetic expression of their targets, which makes them integral components of transcriptional regulatory networks. As sponges (phylum Porifera) are commonly considered the most basal metazoan, the in-depth capture of miRNAs from these organisms provides ...
The biogenesis of human microRNAs (miRNAs) includes two RNA cleavage steps in which the activities of the RNases Drosha and Dicer are involved. miRNAs of diverse lengths are generated from different genes, and miRNAs that are heterogeneous in length are produced from a single miRNA gene. We determined the solution structures of many miRNA precursors and analysed the structural basis of miRNA le...
MiRNAs are a widespread class of small non-coding RNAs that have the ability to silence gene expression through sequence complementarity to their targets. We describe their initial discovery in the nematode C.elegans and review what is currently known about their biogenesis. The regulation of expression and processing of miRNAs, and the mechanisms through which miRNAs locate their correct targe...
The first step in microRNA (miRNA) biogenesis usually involves cleavage at the base of its fold-back precursor. Here, we describe a non-canonical processing mechanism for miRNAs miR319 and miR159 in Arabidopsis thaliana. We found that their biogenesis begins with the cleavage of the loop, instead of the usual cut at the base of the stem-loop structure. DICER-LIKE 1 (DCL1) proceeds then with thr...
MicroRNAs (miRNAs) are short non-coding RNAs that silence mRNAs. They are generated following transcription and cleavage by the DROSHA/DGCR8 and DICER/TRBP/PACT complexes. Although it is known that components of the miRNA biogenesis machinery can be phosphorylated, it remains poorly understood how these events become engaged during physiological cellular activation. We demonstrate that S6 kinas...
A well-defined mechanism governs the maturation of most microRNAs (miRNAs) in animals, via stepwise cleavage of precursor hairpin transcripts by the Drosha and Dicer RNase III enzymes. Recently, several alternative miRNA biogenesis pathways were elucidated, the most prominent of which substitutes Drosha cleavage with splicing. Such short hairpin introns are known as mirtrons, and their study ha...
We recently proposed a specific model whereby miRNAs encoded from short nonautonomous DNA-type TEs known as MITEs evolved from corresponding ancestral full-length (autonomous) elements that originally encoded short interfering (siRNAs). Our miRNA-origins model predicts that evolutionary intermediates may exist as TEs that encode both siRNAs and miRNAs, and we analyzed Arabidopsis thaliana and O...
Increasing evidence indicates that microRNAs (miRNAs) are contributing factors to neurodegeneration. Alterations in miRNA signatures have been reported in several neurodegenerative dementias, but data in prion diseases are restricted to ex vivo and animal models. The present study identified significant miRNA expression pattern alterations in the frontal cortex and cerebellum of sporadic Creutz...
چکیده: لوسمی پرومیلوسیتیک حاد (apl) زیر گروه خاصی از لوسمی میلوئیدی حاد (aml)است که مشخصه بارز آن جابجائی کروموزومی t(15;17)(q22;q12-21)با ایجاد ژن الحاقی pml/rara است. با معرفی درمانهای جدید مانند atra و آرسنیک تری اکساید(as2o3)، apl از یک بیماری بسیارکشنده به یک بیماری بسیار درمان پذیر تبدیل شده است. اثر ضد لوسمی as2o3 هم in vivo و هم in vito کاملا ثابت شده است ولی مکانیسم عملکرد آن هنوز به ...
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