Molecular cloning and expression of the Caenorhabditis elegans klp-3, an ortholog of C terminus motor kinesins Kar3 and ncd.
Common to all eukaryotes, kinesins are cytoskeletal motor proteins that mediate intracellular transport on microtubule tracks, using ATP hydrolysis. A Caenorhabditis elegans cDNA clone corresponding to the klp-3 gene, encoding a novel kinesin, was isolated, and mapped on LGII. Northern blot analysis using the klp-3 cDNA probe reveals a 1.9 kb mRNA that is transcribed at a low level during development. Temporal and spatial expression of the klp-3::lacZ fusion gene is limited to the marginal cells in the pharynx, and a group of muscle cells in the posterior gut region. The nucleotide sequence of klp-3 has been deduced from the cDNA and nematode genome sequencing consortium data. Conceptual translation of the klp-3 gene reveals a kinesin-like protein with its conserved motor domain containing the ATP binding and microtubule binding sites located in the C terminus. KLP-3 shares extensive homology with the yeast Kar3 and Drosophila ncd kinesins, which have previously been shown to mediate chromosomal movement and segregation during meiosis and mitosis. Overexpression of the klp-3 gene partially rescues the lethal phenotype of the maternal lethal him-14 ts(it44) mutants at non-permissive temperatures, and reduces the incidence of males caused by non-disjunction of the X-chromosome. Similarly, expression of a klp-3 antisense RNA, under the control of a heat shock promoter, causes embryonic arrest, dead eggs and polyploid cells in transgenic lines, suggesting a critical role for the klp-3 function in chromosome segregation. Further analysis of the klp-3 gene in C. elegans may elucidate diverse functions of the C terminus mitotic motor proteins during development.
Khan
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ML
Laboratory of Molecular Biology, Department of Ecological Engineering, Toyohashi University of Technology, Toyohashi, 441, Japan.
Gogonea
C B
CB
Siddiqui
Z K
ZK
Ali
M Y
MY
Kikuno
R
R
Nishikawa
K
K
Siddiqui
S S
SS
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D015152:Blotting, Northern; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018076:DNA, Complementary; D029721:Drosophila Proteins; D005656:Fungal Proteins / Q000737:chemistry; D015870:Gene Expression; D017930:Genes, Reporter; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016547:Kinesins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008869:Microtubule-Associated Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D010063:Ovum; D016372:RNA, Antisense / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
D029742:Caenorhabditis elegans Proteins; D018076:DNA, Complementary; D029721:Drosophila Proteins; D005656:Fungal Proteins; D015801:Helminth Proteins; C063504:KAR3 protein, S cerevisiae; C108066:KLP-3 protein, C elegans; D008869:Microtubule-Associated Proteins; D016372:RNA, Antisense; D029701:Saccharomyces cerevisiae Proteins; C066696:ncd protein, Drosophila; D016547:Kinesins