Related Experiment Video
Updated: Jul 30, 2025
10:54
Detection of Retrotransposition Activity of Hot LINE-1s by Long-Distance Inverse PCR
Published on: July 27, 2019
8.7K
Widespread somatic L1 retrotransposition in normal colorectal epithelium
Chang Hyun Nam1, Jeonghwan Youk1,2,3, Jeong Yeon Kim2
1Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea.
Nature
|May 10, 2023
Summary
Somatic cells accumulate genomic alterations via long interspersed nuclear element-1 (L1) retrotransposition, a mobile element. This study reveals L1 activity in normal cells, increasing with age and in colorectal cancer.
Area of Science:
- Genomics
- Molecular Biology
- Epigenetics
Background:
- Genomic alterations accumulate in somatic cells throughout life.
- The role of long interspersed nuclear element-1 (L1) retrotransposition in normal cell mutation landscapes is poorly understood.
Purpose of the Study:
- To investigate the whole-genome sequences of single-cell clones to understand somatic L1 retrotransposition in normal cells.
- To identify the rate, characteristics, and regulation of L1 retrotransposition events across different cell types and ages.
Main Methods:
- Whole-genome sequencing of 899 single-cell clones from 28 individuals.
- Identification and analysis of somatic L1 retrotransposition events.
- Fingerprinting of source L1 elements and multidimensional analysis of retrotransposition activity.
Main Results:
- 1,708 somatic L1 retrotransposition events were identified, enriched in colorectal epithelium and correlated with age.
- Somatic L1 retrotranspositions occur from early embryogenesis, with epigenetic regulation established during organogenesis.
- Retrotransposition-competent L1s with lower allele frequencies showed higher activity, and only a fraction of L1 transcripts were retrotransposed.
Conclusions:
- Somatic L1 retrotransposition contributes to mosaicism in normal cells throughout the human lifespan.
- L1 retrotransposition rates increase significantly during colorectal tumorigenesis.
- This study provides insights into the genomic and epigenomic regulation of transposable elements.
Related Concept Videos
03:18Non-LTR Retrotransposons
11.6K
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...
11.6K
03:08LTR Retrotransposons
17.6K
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...
17.6K
01:23Renewal of Intestinal Stem Cells
2.6K
The intestinal epithelial lining rapidly renews every 4 to 5 days. The renewal is facilitated by intestinal stem cells (ISCs) located at the base of the crypt– a gland located at the bottom of each villus. ISCs divide asymmetrically to form new stem cells and progenitor daughter cells. The daughter cells are called transit-amplifying (TA) cells which move upwards along the crypt and either differentiate into absorptive cells– the enterocytes or secretory cells– including the...
2.6K
02:13Overview of Transposition and Recombination
15.9K
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...
15.9K
02:53Conservative Site-specific Recombination and Phase Variation
6.0K
Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
The recognition sites for Cre recombinase called LoxP...
6.0K
01:33Pleiotropy
40.7K
Pleiotropy is the phenomenon in which a single gene impacts multiple, seemingly unrelated phenotypic traits. For example, defects in the SOX10 gene cause Waardenburg Syndrome Type 4, or WS4, which can cause defects in pigmentation, hearing impairments, and an absence of intestinal contractions necessary for elimination. This diversity of phenotypes results from the expression pattern of SOX10 in early embryonic and fetal development. SOX10 is found in neural crest cells that form melanocytes,...
40.7K