# Host Factors Promoting the LTR Retrotransposon Life Cycle in Plant Cells: Current Knowledge and Future Directions

## TL;DR

This paper reviews how plant cells use their own proteins to help LTR retrotransposons copy and insert themselves into the genome, highlighting gaps in current knowledge and suggesting new research approaches.

## Contribution

The paper proposes integrating mobilomics, genome editing, and interactomics to uncover plant-specific mechanisms of LTR retrotransposon transposition.

## Key findings

- LTR retrotransposons heavily rely on host transcriptional machinery and cellular factors for their life cycle.
- Precise mechanisms of LTR retrotransposon transposition in plants remain poorly understood.
- New methods like transposition reporters and synthetic biology are suggested to study these mechanisms.

## Abstract

Long Terminal Repeat (LTR) retrotransposons (LTR-RTEs) comprise up to 90% of some plant genomes and drive genome diversification through their amplification. Novel insertions arise during the final stages of the LTR-RTE life cycle, which depends on both LTR-RTE-encoded proteins and host cellular factors. The LTR-RTE elements require host transcriptional machinery for RNA production, followed by nuclear processing/export, translation, virus-like particle assembly, reverse transcription, and genomic integration. This review addresses the following question: What host proteins promote LTR-RTE transposition in plants? Our analysis of recent literature on host factors and cellular compartments implicated in the retrotransposition cycle reveals the extensive integration of LTR-RTEs into host processes. Nonetheless, the precise mechanisms remain poorly resolved, especially in plants with their rich repertoire of LTR-RTEs. We propose integrating plant mobilomics with transposition reporters, genome editing, synthetic biology, and interactomics to elucidate plant-specific mechanisms.