...Dianlei Guo; Jiali Ru; Fuxiang Mao; Hong Ouyang; Rong Ju; Kaili Wu; Yizhi Liu; Chunqiao Liu ABSTRACT In terrestrial animals, the lacrimal drainage apparatus evolved to serve as conduits for tear flow; however, little is known about the ontogenesis of this system. Here, we define the anatomy...

... nervous system craniofacial development ontogenesis rat embryo That retinoids are essential for normal embryogenesis has been known for over three quarters of a century. Animal feeding trials identified vitamin A (the prohormone retinol) as essential for normal development. Vitamin A deficiency...

...], suggesting either that there is a considerable functional redundancy among members of the RAR family during ontogenesis or that the RARs are not essential transducers of the retinoid signal in vivo. In order to discriminate between these possibilities, we have generated a series of RAR compound null mutants...

...; and refs therein]. Our results clearly demonstrate that RARs are essential for vertebrate ontogenesis and therefore that retinoic acid is the active retinoid, which is required at several stages of the development of numerous tissues and organs. We discuss several possibilities that may account...