Genomic organization, expression, and chromosome localization of a third aurora-related kinase gene, Aie1

We previously reported two novel testis-specific serine/threonine kinases, Aie1 (mouse) and AIE2 (human), that share high amino acid identities with t he kinase domains of fly aurora and yeast Ipl1. Here, we report the entire intron-exon organization of the Aie1 gene and analyze the expression patter ns of Aie1 mRNA during testis development. The mouse Aie1 gene spans simila r to 14 kb and contains seven exons. The sequences of the exon-intron bound aries of the Aie1 gene conform to the consensus sequences (GT/AG) of the sp licing donor and acceptor sites of most eukaryotic genes. Comparative genom ic sequencing revealed that the gene structure is highly conserved between mouse Aie1 and human AIE2. However, much less homology was found in the seq uence outside the kinase-coding domains. The Aie1 locus was mapped to mouse chromosome 7A2-A3 by fluorescent in situ hybridization. Northern blot anal ysis indicates that Aie1 mRNA likely is expressed at a low level on day 14 and reaches its plateau on day 21 in the developing postnatal testis. RNA i n situ hybridization indicated that the expression of the Aie1 transcript w as restricted to meiotically active germ cells, with the highest levels det ected in spermatocytes at the late pachytene stage. These findings suggest that Aie1 plays a role in spermatogenesis.