Functional characterization and identification of mouse Rad51d splice variants

Area of Science:

• Molecular Biology
• Genomics
• Cellular Biology

Background:

• Homologous recombination (HR) is crucial for genomic integrity, repairing double-stranded breaks and interstrand crosslinks.
• RAD51 paralogs (RAD51B, RAD51C, RAD51D, XRCC2, XRCC3) are essential for HR in vertebrates.
• RAD51D is unique, involved in both HR and telomere maintenance, and interacts with RAD51C and XRCC2.

Purpose of the Study:

• To investigate the interaction of RAD51D splice variants with RAD51C and XRCC2.
• To analyze the expression patterns of different RAD51D splice variants.

Main Methods:

• Yeast-2-hybrid analysis to assess protein interactions.
• EGFP fusion proteins for cellular localization studies.
• Mitomycin C treatment to evaluate functional repair capacity.
• RT-PCR to determine transcript expression patterns.

Main Results:

• RAD51DDelta7b variant interacted with RAD51C and XRCC2; RAD51D+int3 interacted with XRCC2.
• The linker region of RAD51D (residues 54-77) may mediate XRCC2 binding.
• All tested splice variants localized throughout the cell but failed to restore mitomycin C resistance in Rad51d-deficient cells.
• Tissue-specific expression patterns were observed for Rad51dDelta3 and Rad51dDelta5 transcripts.

Conclusions:

• RAD51D alternative splice variants may modulate HR mechanisms.
• These variants potentially exert their function by sequestering RAD51C or XRCC2 proteins.