Genomic organization, transcript variants and comparative analysis of the human nucleoporin 155 (NUP155) gene

Nucleoporin 155 (Nup155) is a major component of the nuclear pore complex (NPC) involved in cellular nucleo-cytoplasmic transport. We have acquired the complete sequence and interpreted the genomic organization of the Nup155 orthologos from human (Homo sapiens) and pufferfish (Fugu rubripes), which are approximately 80 and 8 kb in length, respectively. The human gene is ubiquitously expressed in many tissues analyzed and has two major transcript variants, resulted from an alternative usage of the 5' cryptic or consensus splice donor in intron 1 and two polyadenylation signals. We have also cloned DNA complementary to RNAs of the Nup155 orthologs from Fugu and mouse. Comparative analysis of the Nup155 orthologs in many species, including H. sapiens, Mus musculus, Rattus norvegicus, F. rubripes, Arabidopsis thaliana, Drosophila melanogaster, and Saccharomyces cerevisiae, has revealed two paralogs in S. cerevisiae but only a single gene with increasing number of introns in more complex organisms. The amino acid sequences of the Nup155 orthologos are highly conserved in the evolution of eukaryotes. Different gene orders in the human and Fugu genomic regions harboring the Nup155 orthologs advocate cautious interpretation of synteny in comparative genomic analysis even within the vertebrate lineage.