Koga M et al. (1992) Worm Breeder's Gazette "kin-8 Tyrosine Kinase Gene May Encode a Nerve Growth Factor Receptor of C. elegans"

Koga M, Ohshima YM

[Worm Breeder's Gazette, 1992]

kin-8 is one of the genes for a putative receptor type tyrosine kinase of C. elegans (WBG 11, No.1, 37). Phylogenetic analysis based on amino acid sequences of the tyrosine kinase catalytic domain revealed that kin-8 belongs to a branch of human trk (high affinity nerve growth factor receptor). A phylogenetic tree constructed by Dr. Kei-ichi Kuma is shown below. Furthermore, expression of a kin-8 /lacZchimeric gene was observed strongly around the nerve ring, in ventral cord, tail ganglions, dorsal cord(?), and in pharynx to some extent. These results suggest that kin-8 may encode a receptor for a nerve growth factor (NGF) - like molecule, and that C. elegans may use an NGF-like molecule for development and/or survival of the nervous system. Based on this idea, we tried to clone a gene for NGF in the worm by PCR, but we have not succeeded so far. We are also trying to make a dominant negative kin-8 mutation by in vitro mutagenesis in order to analyze the function of the kin-8 gene. [See Figure 1]