Zebrafish R-cadherin (Cdh4) controls visual system development and differentiation.

In zebrafish, R-cadherin (cadherin-4 or Cdh4) is expressed in the retina and in retinorecipient brain regions, suggesting that Cdh4 functions during visual system development. Cdh4 function was examined during retinogenesis and retinal axon outgrowth using antisense morpholino oligonucleotides and mutant Cdh4 construct expression. In knockdowns, Cdh4 was reduced or absent, eyes were small, and retinae lacked discrete laminae.

Differential expression of cadherins in the developing and adult zebrafish olfactory system.

Cadherins are cell adhesion molecules that play important roles in development of a variety of tissues and maintenance of adult structures. Although cadherin expression has been studied in detail in the central nervous system of several vertebrate species, little is known of their distribution in the developing and adult olfactory structures, and there is no published report, to our knowledge, of cadherin expression in fish olfactory system. In this study, we examined expression patterns of three cadherins, cadherin-1 (E-cadherin), cadherin-2 (N-cadherin), and cadherin-4 (R-cadherin), in the olfactory system of developing and adult zebrafish by using both in situ hybridization and immunocytochemical methods.

E-cadherin regulates cell movements and tissue formation in early zebrafish embryos.

E-cadherin is maternally expressed in most vertebrate species, but its function during early development of the vertebrate embryo proper is unknown. To directly examine E-cadherin gene (cdh1) function in zebrafish, morpholino oligonucleotides (MOs) that inhibit E-cadherin protein (Cdh1) expression were injected into embryos. Cdh1 knockdown reduced embryo survival.