A nematode-specific gene underlies bleomycin-response variation in Caenorhabditis elegans

Shannon C. Brady; Stefan Zdraljevic; Karol W. Bisaga; Robyn E. Tanny; Daniel E. Cook; Daehan Lee; Ye Wang; Erik C. Andersen

We tested if the non-synonymous variant in jmjd-5 between the N2 and CB4856 strains caused 538 bleomycin-response differences. At residue 338 of JMJD-5, the N2 strain has a proline, whereas 539 . CC-BY 4.0 International license is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. It . https://doi.org/10.1101/565218 doi: bioRxiv preprint 25 of 48 the CB4856 strain has a serine (S338P, Figure S9A ). We used CRISPR-Cas9 to generate 540 reciprocal allele replacements of the jmjd-5 single-nucleotide polymorphism that encodes the 541 putative amino-acid change in the N2 background jmjd-5(N2 to CB4856) and in the CB4856 542 background jmjd-5(CB4856 to N2) (Materials and Methods, Supplemental Information). We 543 created two independent allele replacements in each genetic background and measured each 544 strain for bleomycin-response differences as compared to the parental strains ( Figure S9B, File 545 S3 ). Although the allele-replacement strains with the CB4856 allele in the N2 genetic 546 background jmjd-5(N2 to CB4856) were significantly different from the N2 parental strain, these 547 strains were more sensitive to bleomycin than N2 ( Figure S9B , File S7, ECA576 vs. N2 p = 548 0.006, ECA577 vs. N2 p = 1.6e-6, Tukey HSD). This increased sensitivity was unexpected, 549 because the CB4856 allele at the jmjd-5 locus should confer resistance. However, the NIL with 550 the CB4856 genotype across the QTL was not different from the N2 parental strain (ECA232 in 551 Figure S6 , File S7), suggesting that the QTL might only confer increased sensitivity when the 552 N2 allele is in the CB4856 background. Therefore, it remained unclear whether an allele 553 replacement of jmjd-5 in the N2 parental background could confer resistance. Neither of the two 554 strains with the N2 allele in the CB4856 background, jmjd-5(CB4856 to N2), conferred a 555 significantly more sensitive phenotype than the CB4856 parental strain (Figure S9B, File S7) . 556