Human transposon insertion profiling by sequencing (TIPseq) to map LINE-1 insertions in single cells

Area of Science:

• Genomics
• Molecular Biology
• Epigenetics

Background:

• Long Interspersed Element-1 (LINE-1) sequences constitute a significant portion of the human genome and are highly active mobile elements.
• LINE-1 insertions are implicated in genetic diseases and are overexpressed in certain cancers.
• Genome-wide LINE-1 mapping in single cells is crucial for understanding somatic and germline retrotransposition, tumor heterogeneity, and cellular development.

Purpose of the Study:

• To optimize and validate a modified transposon insertion profiling by sequencing (TIPseq) protocol for LINE-1 mapping in single cells.
• To address challenges associated with LINE-1 mapping in single cells, such as chimeric artifacts and repetitive sequence features.

Main Methods:

• Optimization of a modified TIPseq protocol for single-cell analysis.
• Utilizing whole-genome amplification via multiple displacement amplification.
• Employing restriction enzyme digestion, vectorette ligation, and LINE-1-targeted PCR.

Main Results:

• The optimized single-cell TIPseq protocol demonstrated utility for LINE-1 insertion site mapping in lymphoblastoid cells.
• Results from single-cell TIPseq experiments showed good correlation with established LINE-1 insertion data from whole-genome sequencing and bulk TIPseq.
• The selected method, involving multiple displacement amplification and subsequent molecular steps, exhibited superior assay performance.

Conclusions:

• The developed single-cell TIPseq method provides a robust tool for high-resolution LINE-1 insertion analysis.
• This advancement facilitates detailed studies on the role of LINE-1 in genetic variation, disease pathogenesis, and cellular evolution.
• The findings pave the way for deeper investigations into the impact of LINE-1 retrotransposition across various biological contexts.