Worm Breeder's Gazette 11(4): 67

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 unc-104 Product Contains Homologies to Kinesin Heavy Chain

Anthony Otsuka, Ayyamperumal Jeyaprakash, Jaime Annoveros-Garcia, Lan Tang, Greg Fisk and Teresa Born

Figure 1

The unc-104 mutant defects include: 1) a reduced number of vesicles 
in the presynaptic region and their accumulation in the cell bodies, 2)
a decrease in the volume of the synaptic region, 3) the reduction of 
presynaptic electron dense material, 4) the loss of neuromuscular 
junctions, and 5) improper growth of the muscle arms (Hall, D. H.  et 
al., Soc.  Neurosci.  Abstr., 15, 1388 (1989) ) .  
In a search of Genbank (March 1990, v.  63) the unc-104 protein 
demonstrated homology to the ATPase and tubulin binding region of the 
kinesin heavy chain (46% identity in 240 amino acids), and a potential 
secondary structure similar to kinesin.  The homology is strongest in 
the ATP-binding domain (see figure below).
In other organisms, kinesin is believed to be involved in neuronal 
anterograde fast axonal transport and in microtubule-based movement in 
other cell types (for a review see McIntosh, J. R and Porter, M. E., J.
Biol .  Chem., 264 , 6001-6004 (1989)).  Kinesin is a dimer of heavy 
chains (110-134 kDA), each associated with a light chain (60-80 kDa).  
The ATPase and microtubule-binding domains are located in the globular 
head near the heavy chain amino terminus, although in some kinesin-
related proteins the 'motor' domain is at the carboxyl end.    The unc-
104 protein (approximately 1600 amino acids) is larger than Drosophila 
kinesin (975 amino acids) and squid axon kinesin (967 amino acids).  
Further studies will be required to determine whether the unc-104 
protein is functionally equivalent to kinesin.  Because of the 
excellent genetics of the nematode, it should be a useful system for 
studying the role of kinesin-like proteins in axonal transport and 
[See Figure 1]

Figure 1