Genomic organization and molecular characterization of the human ninein gene

The centrosome plays a key role in the formation of the mitotic spindle, ce ll polarity, and cell locomotion. Previously we identified a novel centroso mal associated protein HNinein using GSK-3 beta as a bait in the yeast two- hybrid. In this report, the HNinein genome was found to correspond to 29 ex ons of genomic sequence on human chromosome 14q22, Promoter analysis predic ts that hNinein contains a TATA, two CCAAT, and three GC boxes. The promote r exhibits the following potential transcription factor binding sites: Spl, p300, and AP-1. In addition, an alternatively spliced isoform, encoded a 2 041-amino-acid protein of 237,900 Pa, which was designated hNinein-Lm (Gen- Bank AF302773). The hNinein-Lm genome was found to correspond to 28 exons ( 2'-29). Amino acid sequence comparison with hNinein showed that hNinein-Lm exhibited an EF-hand Ca2+ binding domain in the N-terminus which similar to mouse ninein. Northern blot showed that this hNinein-Lm isoform was expres sed more than hNinein in tissues examined. Differential RT-PCR combining So uthern blotting also showed that hNinein-Lm is much more abundant compared to hNinein. Two forms of ninein may also imply the status of ninein associa ted with a pair of the centrioles in the centrosome structure. Furthermore, molecular characterization shows that human ninein is oligomerized at the C-terminal end which overlapped with GSK-3 beta binding site, suggesting th at oligomerization of ninein may be regulated by GSK-3P phosphorylation, (C ) 2000 Academic Press.