MPK-1/ERK pathway regulates DNA damage response during development through DAF-16/FOXO

Area of Science:

• Molecular Biology
• Genetics
• Developmental Biology

Background:

• Ultraviolet (UV) radiation causes DNA lesions, stalling RNA polymerase II (RNAP II).
• Transcription-coupled nucleotide excision repair (TC-NER) removes these lesions.
• Mutations in human TC-NER genes CSA and CSB cause Cockayne syndrome, leading to developmental defects.

Purpose of the Study:

• Identify genetic suppressors of developmental defects in UV-exposed C. elegans csb-1 mutants.
• Investigate the role of the RAS-MAPK pathway in the DNA damage response.

Main Methods:

• Genetic suppressor screen in C. elegans.
• UV irradiation of C. elegans strains.
• Analysis of developmental growth and gene expression.

Main Results:

• Mutations in the ERK1/2 MAP kinase gene mpk-1 suppressed UV-induced developmental growth arrest in TC-NER mutants.
• Constitutive activation of the RAS-MAPK pathway worsened DNA damage-induced growth arrest.
• MPK-1 acts through the insulin/IGF signaling pathway to regulate DAF-16 (a FOXO transcription factor).

Conclusions:

• The MPK-1 pathway is a key regulator of the developmental response to DNA damage in C. elegans.
• MPK-1, via insulin signaling and DAF-16, mediates developmental plasticity following DNA damage.
• This study reveals a conserved mechanism linking DNA repair, MAPK signaling, and development.