Figure 3

Clone 1030 is derived from a new member of the kinesin superfamily. A. The genomic structure of 1030-derived genes on chromosomes 9, 13 and 17 of human, mouse and rat, respectively, are depicted with numbered vertical bars representing exons. The rat sequence was construc ted from four separate contigs (RNOR01052409, RNOR01052410, RNOR01052411 and RNOR01052412, Accession numbers: AABR02079933, AABR02039869, AABR02135902 and AABR02012418) and the arrowheads indicate the positions of short gaps in the genomic sequence. B. PCR analysis of human testis cDNA reveals the presence of three alternatively spliced isoforms. Human testis cDNA was amplified with primers designed to amplify bases 2118–3129 of the predicted full length cDNA based on the genomic structure described above. Three discrete products were observed and are indicated with asterisks. These products were isolated, subcloned and sequenced and corresponded to cDNAs resulting from alternatively spliced mRNAs. The relative proportions of the three products varied in different cDNA preparations although the shortest product was generally the predominant product (data not shown). Key: M: 100bp marker ladder; T: human testis cDNA; T/10: one-tenth of human testis cDNA loaded in previous lane. C. The structure of transcripts derived from the human gene was analyzed by RT-PCR yielding three mRNAs that result from alternative splicing. The exon distribution of each mRNA is indicated (exon 1 is non-coding and was omitted) along with the size of the predicted protein. This protein has now been named KIF27 with a prefix to indicate the species and a letter to indicate the splice variant. Kinesins are characterized by a ~300 amino acid motor domain that is located at the N-terminus of KIF27. The N-5 subgroup of kinesins also possesses a characteristic neck domain at the C-terminal end of the motor domain. A comparison of the KIF27 neck domain with the corresponding domain of KIF4 is shown, with conserved amino acids indicated between the sequences and in upper case letters within each sequence. Key: φ: hydrophobic residue.