Adaptive P-element insertions in a long non-coding RNA are associated with unique silencing properties

Area of Science:

• Genetics
• Molecular Biology
• Evolutionary Biology

Background:

• Transposable elements (TEs) are mobile genetic sequences that can cause mutations.
• While often deleterious, TE insertions can be adaptive, influencing host gene expression or function.
• piRNA clusters are known to mediate TE silencing, but other genomic regions can also play a role.

Purpose of the Study:

• Investigate the functional consequences of P-element insertions in the CR43651 long non-coding RNA (lncRNA) in Drosophila melanogaster.
• Determine the impact of these insertions on P-element transcriptional regulation, piRNA biogenesis, and host viability.
• Elucidate the adaptive mechanisms and potential trade-offs associated with these TE insertions.

Main Methods:

• Analysis of P-element insertions within the CR43651 lncRNA locus.
• Assessment of piRNA production and silencing during oogenesis.
• Evaluation of host viability and fitness in the presence of CR43651 insertions.
• Examination of microRNA (miRNA) production, specifically mir14.

Main Results:

• CR43651 is an insertion hotspot for P-elements, contributing to adaptive benefits.
• Antisense P-element insertions in CR43651 enhance piRNA-like silencing during oogenesis, a critical period for P-element transposition.
• Despite silencing benefits, these insertions exhibit recessive viability effects, potentially linked to disrupted mir14 production.

Conclusions:

• CR43651, though not a canonical piRNA cluster, can mediate adaptive TE silencing.
• P-element insertions in CR43651 provide a fitness advantage through enhanced transposition repression.
• Disruption of mir14 production by these insertions leads to a trade-off, impacting host viability.