Hello,
Does anyone know of any DNA/RNA repair proteins that can be used as a marker to detect localised damage within the nucleoli of cells - such as exposure to radiation?
Nucleoli are made up of mostly RNA so if they received exposure to radiation producing single stranded breaks, would these be repaired by DNA repair proteins or RNA proteins?
Thank you for any help or guidance
As far as I know, RNA damage is generally not repaired; rather, they are degraded as part of quality control in favor of de novo synthesis. Consider that DNA repair is possible because a complementary strand is available; that isn't the case with RNA. Some DNA repair enzymes, like AP endonuclease, do have a dual role in DNA repair and RNA quality control.
I'm not sure if there are nucleolar-specific DNA damage responses, at least not specific enough to use as a marker.
Look up Histone H2AX phosphorylation as a marker for DNA damage. May work in your case. Histone H2AX phosphorylation is not specific for nucleolus but it will happen in nucleolus too.
WRN Helicase has been reported to translocate from nucleoli into the nucleoplasm upon DNA damage. I am not aware of any RNA damage repair pathway, but in my opinion such a pathway would not make sense.
Try H2AX for non-specific marker, or SMC-1, CTCF if they are related to your work.
Like the other answer before, I'm not aware of RNA damage.
If you want localise damage use an antibody against gammaH2AX which is specific for double strand break, or you can label PARP which is specific to single strand break (both described for DNA).
Good luck!
Histone H2B phosphorylated at serine 14 has been reported to mark nucleolar chromatin following ionizing irradiation, where MST2 kinase localizes at the nucleoli and targets phosphorylation of H2BS14p in an ATM-dependent manner
https://pubmed.ncbi.nlm.nih.gov/29789391/
Radiation-induced changes in nucleolin (a nucleolar marker) have also been reported and role of p53 has been suggested.
https://pubmed.ncbi.nlm.nih.gov/31578593/
https://pubmed.ncbi.nlm.nih.gov/30839063/
https://pubmed.ncbi.nlm.nih.gov/23145133/
PICT-1 (ribosome biogenesis factor) has been suggested as a major nucleolar sensor of the DNA damage repair response to UVB radiation and an important upstream regulator of p53 via the RPL11-MDM2-p53 pathway.
https://pubmed.ncbi.nlm.nih.gov/27829214/
The following papers may also be relevant.
https://pubmed.ncbi.nlm.nih.gov/29364875/
https://pubmed.ncbi.nlm.nih.gov/26208041/
https://pubmed.ncbi.nlm.nih.gov/22419112/
https://pubmed.ncbi.nlm.nih.gov/21778410/
https://pubmed.ncbi.nlm.nih.gov/21741933/
https://pubmed.ncbi.nlm.nih.gov/18443037/
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