Related Experiment Video
Updated: May 8, 2026
11:52
Analysis of LINE-1 Retrotransposition at the Single Nucleus Level
Published on: April 23, 2016
The Microprocessor controls the activity of mammalian retrotransposons
Sara R Heras1, Sara Macias, Mireya Plass
11] Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK. [2] Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government (GENYO), Granada, Spain. [3].
Nature Structural & Molecular Biology
|September 3, 2013
Summary
The Microprocessor complex (Drosha-DGCR8) represses transposable elements like LINE-1 and Alu. This discovery reveals a new role for the Microprocessor in maintaining human genome integrity.
Area of Science:
- Genetics
- Molecular Biology
- Epigenetics
Background:
- Transposable elements constitute over half of the human genome.
- Their mobilization drives genetic diversity, but host regulation remains unclear.
Purpose of the Study:
- Investigate the Microprocessor complex's role in regulating transposable element activity.
- Determine if the Microprocessor complex impacts LINE-1, Alu, and SVA retrotransposons.
Main Methods:
- RNA immunoprecipitation to identify Microprocessor binding targets.
- Expression analysis in cells with and without functional Microprocessor.
- In vitro cleavage assays using Drosha.
- Cell culture-based retrotransposition assays.
Main Results:
- The Microprocessor complex binds RNAs from LINE-1, Alu, and SVA retrotransposons.
- Cells lacking Microprocessor show increased LINE-1 mRNA and protein.
- Drosha cleaves LINE-1 mRNA structures in vitro.
- Microprocessor negatively regulates LINE-1 and Alu retrotransposition in vivo.
Conclusions:
- The Microprocessor complex acts as a post-transcriptional repressor of mammalian retrotransposons.
- This function contributes to the maintenance of human genome integrity.
- Identifies a novel defense mechanism against mobile genetic elements.
More Related Videos
Related Concept Videos
03:08LTR Retrotransposons
LTR retrotransposons are class I transposable elements with long terminal repeats flanking an internal coding region. These elements are less abundant in mammals compared to other class I transposable elements. About 8 percent of human genomic DNA comprises LTR retrotransposons. Some of the common examples of LTR retrotransposons are Ty elements in yeast and Copia elements in Drosophila.
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
03:18Non-LTR Retrotransposons
As the name suggests, non-LTR retrotransposons lack the long terminal repeats characteristic of the LTR retrotransposons. Additionally, both LTR and non-LTR retrotransposons use distinct mechanisms of mobilization. Non-LTR retrotransposons are further divided into two classes - Long interspersed nuclear elements (LINEs) and short interspersed nuclear elements (SINEs), both of which occur abundantly in most mammals, including humans. Some of the active non-LTR retrotransposons in humans are L1...
02:57DNA-only Transposons
DNA-only transposons are called autonomous transposons since they code for the enzyme transposase that is required for the transposition mechanism. Insertion of transposons can alter gene functions in multiple ways. They can mutate the gene, alter gene expression by introducing a novel promoter or insulator sequence, introduce new splice sites, and change the mRNA transcripts produced, or remodel chromatin structure.
The donor site from where the transposon is excised is either degraded or...
The donor site from where the transposon is excised is either degraded or...
02:33Retroviruses
Retroviruses and retrotransposons both insert copies of their genetic elements into the genome of the host cell. Thus, the viral genes are passed on when the host genome is replicated or translated. A typical retroviral DNA sequence contains 3-4 genes that encode the different proteins required for its structural assembly and function as a molecular parasite. This DNA is transcribed into a single mRNA, which is very similar in structure to conventional mRNAs, i.e., it is capped at the 5’...
01:24Transposons
Transposons, or "jumping genes," are small mobile genetic elements (MGEs) that range from 700 to 40,000 base pairs in length. They are found in all organisms and can move within the same chromosome or transfer to different chromosomes. In some cases, transposons can also jump between different host DNA molecules, such as plasmids or viruses, contributing to genetic variability.Barbara McClintock first discovered these mobile genetic elements in the 1940s while studying maize genetics, and she...
02:13Overview of Transposition and Recombination
Transposons make up a significant part of genomes of various organisms. Therefore, it is believed that transposition played a major evolutionary role in speciation by changing genome sizes and modifying gene expression patterns. For example, in bacteria, transposition can lead to conferring antibiotic resistance. Movement of transposable elements within the genetic pool of pathogenic bacteria can aid in transfer of antibiotic-resistant genetic elements. In eukaryotes, transposons can carry out...