RP gene haploinsufficiency promotes extra sensory organ formation via a threshold effect

Haiwei Pi1,2, Kuan-Han Chen1, Hsin Tu1,2

  • 1Department of Biomedical Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan.

Fly
|January 6, 2026
PubMed

Insights

Ribosomal protein (RP) gene haploinsufficiency causes ribosomopathies. In Drosophila, severe RP defects trigger a threshold effect, promoting sensory organ formation via Xrp1, suggesting a stress response mechanism.

Area of Science:

  • Developmental Biology
  • Genetics
  • Cell Biology

Background:

  • Ribosomal protein (RP) gene haploinsufficiency leads to ribosomopathies.
  • In Drosophila, this manifests as the Minute phenotype, affecting mechanosensory bristles.
  • Bristle and campaniform sensilla (CS) development relies on Achaete (Ac) and Scute (Sc) proteins.

Purpose of the Study:

  • Investigate the genetic interactions between RP gene haploinsufficiency and sensory organ development.
  • Identify mechanisms underlying threshold-dependent effects in severe Minute phenotypes.
  • Explore the role of stress-response pathways in modulating neurogenesis.

Main Methods:

  • Analyzing genetic interactions between ac sc and Minute mutants.
  • Comparing transcriptomes of sensory organ-promoting and non-promoting Minutes.
  • Investigating the effect of Xrp1 mutations on ectopic CS formation.

Main Results:

  • A novel bristle-promoting effect was identified in strongly affected Minutes, dependent on bristle length threshold.
  • This threshold effect promotes ectopic campaniform sensilla (CS) formation.
  • Elevated Xrp1-Irbp18 dimer expression was observed in Minutes exhibiting these phenotypes.
  • Xrp1 mutation suppressed ectopic CS formation, indicating a positive regulatory role.

Conclusions:

  • RP gene haploinsufficiency exhibits a previously unrecognized threshold effect.
  • Excessive Xrp1 activity promotes supernumerary sensory organ formation under severe ribosomal stress.
  • This suggests a compensatory mechanism modulating neurogenesis during severe ribosomal stress.

Related Concept Videos

Pleiotropy01:33

Pleiotropy

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,...
43.2K
Exon Recombination02:32

Exon Recombination

The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes. 
Exon shuffling follows “splice frame rules.” Each exon...
4.1K