Worm Breeder's Gazette 15(4): 33 (October 1, 1998)

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.

Characterization of C. elegans homolog of Neurabin, a novel actin-filament binding protein.

Tooru Ishitani, Naoki Hisamoto, Kunihiro Matsumoto

Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku Nagoya JAPAN

 Transmembrane proteins, such as adhesion molecules, receptors, and
channels, are often associated with the actin-filament. The association
between the actin-filament and the plasma membrane plays crucial roles in
various cellular events, such as cell adhesion, cell motility, and cell
shape determination. Neurabin-I and -II are novel actin-filament binding
proteins purified from rat brain. Neurabin-I is localized at the synapse in
the mature nervous system, and implicated in neurite formation. On the
other hand, Neurabin-II is enriched at synapse and cadherin-based cell-cell
adhesion sites. We isolated a Neurabin homolog from C. elegans genomic
database, and termed it nab-1(Neurabin homolog-1). Similar to rat
Neurabins, NAB-1 has one PDZ domain, one protein phosphatase1(PP1)-binding
domain, and several domains predicted to form coiled-coil structures(see

[Figure 1]

 We created a nab-1::gfp translational fusion construct to investigate the
nab-1 expression pattern. The nab-1::gfp was expressed in the hypodermal
progenitor cells during gustrulation. GFP-staining persisted in the
hypodermal cells through L2. In young adult stage, expression was detected
in a pair of the amphid chemosensory neurons.
 To investigate the role of nab-1, we performed RNA-mediated
interference(RNAi) experiment. Most of nab-1(RNAi) worms were embryonic
lethal. These lethal embryos arrested before organogenesis. A few embryos
survived, and all of them showed dumpy and left-handed roller phenotypes.
Some of them also showed the defects in the germ-line formation and vulval
formation (such as protreuding-vulva). 
 These data suggest that nab-1 is essential for embryogenesis. The
hypodermal cells from embryo to L2 stage do the most active morphogenetic
movement in development. One possibility is that NAB-1 may participate in
the migration or cell-shape determinmation of hypodermal cells during