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LINE-1: creators of neuronal diversity
Charles A Thomas1, Alysson R Muotri
1Department of Pediatrics, Rady Children's Hospital San Diego and Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093, USA.
Frontiers in Bioscience (Elite Edition)
|December 29, 2011
Summary
Long interspersed nucleotide elements (L1s) actively retrotranspose in neuronal progenitor cells, influencing brain evolution and individual neuron transcriptomes. This activity is linked to neurogenesis, similar to the NeuroD1 gene.
Area of Science:
- Genomics
- Neuroscience
- Molecular Biology
Background:
- Long interspersed nucleotide elements (L1s) are non-LTR retrotransposons that shape mammalian genomes.
- L1 retrotransposition historically linked to germ cells and cancer, but recent findings reveal activity in neural progenitor cells (NPCs).
- L1 insertions contribute significantly to genome expansion, with over 30% of the human genome attributed to L1 activity.
Purpose of the Study:
- To investigate the activity and implications of L1 retrotransposition in neuronal progenitor cells.
- To understand the impact of L1 insertions on neuronal transcriptional expression and individual neuron transcriptomes.
- To explore the relationship between L1 element activation and neurogenesis.
Main Methods:
- Analysis of L1 retrotransposition activity in mouse, rat, and human NPCs.
- Quantification of L1 insertions in brain regions like the hippocampus.
- Comparison of L1 transcriptional activation patterns with NeuroD1 gene expression.
Main Results:
- L1 elements are highly active in neuronal progenitor cells across species.
- Multiple L1 insertions per cell are estimated in brain regions such as the hippocampus.
- L1 insertions significantly alter neuronal transcriptional expression, contributing to unique neuronal transcriptomes.
- L1 transcriptional activation parallels NeuroD1 gene activation during neurogenesis.
Conclusions:
- L1 retrotransposition is a significant factor in brain evolution and neuronal diversity.
- L1 activity in NPCs suggests a critical role in neurogenesis and brain development.
- The findings highlight L1 elements as key players in shaping neuronal identity and function.
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