Identification and characterization of human LL5A gene and mouse Ll5a gene in silico.

ARCN1, KIAA0638, TREH, DDX6, BLR1, BCL9L, UPK2, DLNB13, DLNB14, RPS25, SBDN, G6PT1, HYOU1, VPS11, HMBS, H2AFX, DPAGT1, KIAA0285, MIZF, ABCG4, NOD9, PDZK2, CBL, MCAM, RNF26, C1QTNF5, MFRP, USP2, THY1, and PVRL1 genes are located within the commonly deleted region of neuroblastoma at human chromosome 11q23.3. Here, we characterized the KIAA0638 gene within the 11q23.3 region by using bioinformatics. Because human KIAA0638 gene was homologous to human LL5B gene encoding LL5beta protein, KIAA0638 was designated LL5A gene encoding LL5alpha protein. LL5A isoform 1 (FLJ00141 type) consists of exons 1-12, 14-21 and 23, while LL5A isoform 2 (KIAA0638 type) consists of exon 1-23. LL5A isoform 1 was the major transcript among LL5A isoforms generated due to alternative splicing. Nucleotide sequence of mouse Ll5a cDNA was determined by assembling CB522359 EST and 5'-truncated mKIAA0638 cDNA. Human LL5alpha isoform 2 showed 94.4 and 35.9% total-amino-acid identity with mouse Ll5alpha and human LL5beta, respectively. LL5alpha proteins consist of Forkhead associated (FHA) domain, bipartite nuclear localization signal (NLS), Chromosome segregation ATPases (SMC) domain, and Pleckstrin homology (PH) domain. LL5alpha proteins were homologous to PtdIns(3,4,5)P3 sensor protein LL5beta in the SMC and PH domains, and were also homologous to KIF1A, KIF1B, KIF13A, KIF13B, KIF14, and SNX23 proteins in the FHA domain. LL5alpha protein might be a transducer of PtdIns(3,4,5)P3 levels to the intracellular trafficking system.