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Unformatted text preview: Cadherin-4 Plays a Role in the Development of Zebrafish Cranial Ganglia and Lateral line System Amy L. Wilson 1 , Shen Yu-chi 2 , Sherry G. Babb-Clendenon 3 , Jason Rostedt 1 , Bei Liu 1 , Kate F. Barald 2 , James A. Marrs 3 , and Qin Liu 1,* 1 Department of Biology, University of Akron, Akron, Ohio 44325-3908 2 Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-0616 3 Department of Medicine, Indiana University Medical Center, Indianapolis, Indiana 46202 Abstract We previously reported that cadherin4 (also called R-cadherin) was expressed by the majority of the developing zebrafish cranial and lateral line ganglia. Cadherin4 function in the formation of these structures in zebrafish was studied using morpholino antisense technology. Differentiation of the cranial and lateral line ganglia, and lateral line nerve and neuromasts of the cadherin4 morphants was analyzed using multiple neural markers. We found that a subset of the morphants cranial and lateral line ganglia were disorganized, smaller, with reduced staining, and/or with altered shape compared to control embryos. Increased cell death in the morphant ganglia likely contributed to these defects. Moreover, cadherin4 morphants had shorter lateral line nerves and reduced number of neuromasts, which was likely caused by disrupted migration of the lateral line primordia. These results indicate that cadherin4 plays a role in the normal formation of the zebrafish lateral line system and a subset of the cranial ganglia. Keywords zebrafish; development; lateral line nerve, neuromasts; cell adhesion molecules; cranial nerves Introduction The vertebrate cranial ganglia and lateral line systems originate from neural crest and epidermal placodes (Northcutt and Gans, 1983; Hall, 1999). The zebrafish cranial ganglia, located ventrolateral to the hindbrain, consist of the trigeminal (gV), facial (gVII), statoacoustic (gVIII), glossopharyngeal (gIX), and vagal (gX) ganglia (Raible and Kruse, 2000). The gV becomes recognizable as early as 9 hours post fertilization (hpf), the earliest of the cranial ganglia (Andermann et al., 2002). The gVIII is formed from delaminating otic epithelium between 22-30 hpf (Haddon and Lewis, 1996). The remaining cranial ganglia (gVII and gX) are formed later (after 36 hpf). The zebrafish lateral line system contains four ganglia and sets of neuromasts (Metcalfe, 1985; 1989; Raible and Kruse, 2000). The posterior lateral line ganglion (gP), caudal to the otic vesicle, can be recognized as early as 14 hpf (Andermann et al., 2002). The anterodorsal ganglion (gAD) and anteroventral ganglion (gAV), located anterior to the otic vesicle, develop from the anterior lateral line placode area around 24 hpf, while the middle lateral line ganglion (gM), located anteromedial to the gP, develops after 26 hpf (Andermann et al., 2002). The gAD and gAV partially fuse with gV and the gVII, respectively *To whom correspondence should be addressed. Phone: 330-972-7558; Fax: 330-972-8445; E-mail: email@example.com.*To whom correspondence should be addressed....
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