NEIL1 mRNA splicing variants are expressed in normal mouse organs

Oxidized pyrimidines are mainly repaired by base excision repair,which is initiated by damagespecific dna glycosylases. neil1,the mammalian homolog of escherichia coli endonuclease viii and a major dna glycosylase,initiates repair of oxidized pyrimidines. here,we investigated the expression of two putative variant mouse neil1 (mneill) mrnas-variant 1 (neil 1 protein mrna; bc043297 in the ncbi database) and variant 2 (unnamed protein mrna; ak040802 in the ncbi database)-in normal mouse organs. reverse transcription-pcr showed that both mrnas were expressed in total rna samples from 9 organs. immunoblot analysis of a nuclear extract from normal mouse liver revealed three bands corresponding to full-length mneill protein and the two predicted variant proteins. however,neither variant protein,which included an n-terminal enzymatic activity domain deduced from the mrna variants,were enzymatically active under multiple reaction conditions when expressed as his-tagged recombinant proteins. nevertheless,recombinant variant 1 protein influenced mneill activity,while recombinant variant 2 protein had no influence. these results suggest that mneill mrna variants are expressed in a variety of organs in normal mice and that variant 1 protein may regulate mneill activity.