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.
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 below). [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 embryogenesis.