Worm Breeder's Gazette 15(5): 36 (February 1, 1999)

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

The Extended (Worooom) Superfamily of Kinesin Motors in Caenorhabditis elegans

M.Yusuf Ali1, M.Liakot Ali Khan1, Fumitoshi Hori1, Shams T. Khan1, Zeba K. Siddiqui2, Shahid S. Siddiqui3

1 Laboratory of Molecular Biology, Dept of Ecological Engineering,, Toyohashi University of Technology, Toyohashi 441-8580, Japan
2 Northwestern University, Dept of BMBCB, Evanston, IL 60208
3 University of Illinois, Dept of Pharmacology, Chicago, IL 60612

In eukaryotes, kinesins are cytoskeletal motor proteins that
mediate intracellular transport of a variety of vesicles and
cellular cargo on microtubule tracks, by hydrolysing ATP. We
have previously characterized cDNA clones corresponding to 20
genes (klp-1 to klp-20) encoding members of the kinesin super
family (Khan et al.,JMB,270,627-639,1997). Using maximum parsimony 
rules, and ProtML program implemented on the MOLPHY package,
we have constructed a phylogenetic tree derived from the motor
domain regions of different kinesins. Based on the results of 
this computation, we have been able to assign nemtaode kinesins
in eight distinct classes, and one  outgroup where atypical 
kinesins which do not match with any of the above eight classes
in structure have been placed. It is remarkable that the nematode 
genome encodes representatives of all the known kinesin groups 
found in mammals (e.g. see Hirokawa, 1996, 1998)

To determine the temporal and spatial expression pattern of
different kinesin like proteins, we have systematically 
investigated the transcription of these genes by using in 
situ hybridization on whole mount embryos, using digioxiginine 
labeled cDNA probes from representative kinesins from all nine 
groups. Our results suggest that multiple kinesins co-express 
in early embryogenesis in C.elegans, and some of these show 
cell lineage specificity. These results provide the first 
complete view of the temporal and spatial expression pattern 
of the kinesin  superfamily in a metazoan during early development. 
We have also used the dsRNAi assay, (Tabara,1998, Fire,1998)
for different members of the  kinesin gene family to see the
resulting phenotypes in the treated animals. Our results are
consistent with the predicted roles of different kinesins involved 
in early embryonic development, such as chromosome movement, 
and spindle pole orientation (Khan et al., 1997). For example, 
klp-3 encoded C-terminus retrograde kinesin like protein, 
and the  Chromoskinesin ortholog  (CeKLP-12) also helps in 
chrmosomal locomotion.

We have also performed the in situ  hybridization of kinesin
genes during larval and adult development. Our data  suggest
differential expression for various members of the kinesin 
gene family, in a variety of tissues such as the nervous 
system, musculature, gonads, and hypodermis. For a higher
resolution of kinesin gene expression, we are in the process 
of constructing gfp fusion reporter genes (A. Fire et al.),
and analyzing the ectopic expression of the reporter genes 
in different kinesin mutant backgrounds.Finally we have been 
able to assign some of the previously uncharcaterized cDNA 
clones to newly released genomic sequences,that brings the
total number of kinesin like proteins to about 25. These new
kinesin motors soon will be part of the big motor city once 
their wheels are checked, and properly aligned.

We thank Yuji Kohara, and the sequencing consortium for their 
continued generosity by providing us with necessary parts for 
the motor family.