Insertion at position 359 of the Kdm4B 5' UTR.
The P{PZ}Aats-val03531 insertion is identified as an allele of Aats-val on genetic grounds (fails to complement Aats-valk14312) as well as an allele of Kdm4B on molecular grounds (it is within the Kdm4B transcription unit).
Heterozygous flies are significantly more sensitive to UV irradiation than wild-type controls.