Clusters of microRNAs emerge by new hairpins in existing transcripts

نویسندگان

  • Antonio Marco
  • Maria Ninova
  • Matthew Ronshaugen
  • Sam Griffiths-Jones
چکیده

Genetic linkage may result in the expression of multiple products from a polycistronic transcript, under the control of a single promoter. In animals, protein-coding polycistronic transcripts are rare. However, microRNAs are frequently clustered in the genomes of animals, and these clusters are often transcribed as a single unit. The evolution of microRNA clusters has been the subject of much speculation, and a selective advantage of clusters of functionally related microRNAs is often proposed. However, the origin of microRNA clusters has not been so far explored. Here, we study the evolution of microRNA clusters in Drosophila melanogaster. We observed that the majority of microRNA clusters arose by the de novo formation of new microRNA-like hairpins in existing microRNA transcripts. Some clusters also emerged by tandem duplication of a single microRNA. Comparative genomics show that these clusters are unlikely to split or undergo rearrangements. We did not find any instances of clusters appearing by rearrangement of pre-existing microRNA genes. We propose a model for microRNA cluster evolution in which selection over one of the microRNAs in the cluster interferes with the evolution of the other linked microRNAs. Our analysis suggests that the study of microRNAs and small RNAs must consider linkage associations.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Beyond Secondary Structure: Primary-Sequence Determinants License Pri-miRNA Hairpins for Processing

To use microRNAs to downregulate mRNA targets, cells must first process these ~22 nt RNAs from primary transcripts (pri-miRNAs). These transcripts form RNA hairpins important for processing, but additional determinants must distinguish pri-miRNAs from the many other hairpin-containing transcripts expressed in each cell. Illustrating the complexity of this recognition, we show that most Caenorha...

متن کامل

Prediction of human microRNA hairpins using only positive sample learning

MicroRNAs (miRNAs) are small molecular non-coding RNAs that have important roles in the post-transcriptional mechanism of animals and plants. They are commonly 21-25 nucleotides (nt) long and derived from 60-90 nt RNA hairpin structures, called miRNA hairpins. A larger number of sequence segments in the human genome have been computationally identified with such 60-90 nt hairpins, however the m...

متن کامل

Mammalian microRNAs derived from genomic repeats.

In this article, we show that a subset of conventional mammalian microRNAs is derived from LINE-2 transposable elements and other genome repeats. These repeat-derived microRNAs arise from conventional precursor hairpins and are distinct from the rasiRNAs, which appear to be processed from long double-stranded RNA precursors. The insertion of transposable elements into new genomic sites appears ...

متن کامل

Reliable prediction of Drosha processing sites improves microRNA gene prediction

MOTIVATION Mature microRNAs (miRNAs) are processed from long hairpin transcripts. Even though it is only the first of several steps, the initial Drosha processing defines the mature product and is characteristic for all miRNA genes. Methods that can separate between true and false processing sites are therefore essential to miRNA gene discovery. RESULTS We present a classifier that predicts 5...

متن کامل

Uridylation of RNA Hairpins by Tailor Confines the Emergence of MicroRNAs in Drosophila

Uridylation of RNA species represents an emerging theme in post-transcriptional gene regulation. In the microRNA pathway, such modifications regulate small RNA biogenesis and stability in plants, worms, and mammals. Here, we report Tailor, an uridylyltransferase that is required for the majority of 3' end modifications of microRNAs in Drosophila and predominantly targets precursor hairpins. Uri...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره 41  شماره 

صفحات  -

تاریخ انتشار 2013