Monoclonal antibody GL1 and its possible involvement in the morphogenesis of the otic vesicle

In a previous study, a monoclonal antibody (MAB) named GL1 was identified t hat is expressed in a precise pattern during gastrulation and early neurula tion stages in chick embryos. In this article we have further investigated the expression pattern of this MAB in the chick embryo. GL1 antigen is pres ent in several organs that seem not to be related developmentally. Among th em, GL1 is present during the early steps of the otic placode formation, in the pharyngeal endoderm, in some neural crest cells, in the somites, and i n the ventricular surface of the nervous system. The distribution in the ne rvous system is well patterned with two broad lines of expression in the ve ntricular side of the metencephalic region, a unique and centered expressio n in the border between the metencephalon and the myelencephalon and again in two lines running along the myelencephalon and the rostral spinal cord. Additionally GL1 can be induced by members of the FGF family, and we have u sed this system to elucidate its role in otic placode formation. The result s obtained reveal that GL1 can be a useful marker for the study of developm ental processes in the endoderm, the otic anlage, and the apical surface of the nervous system. Biochemical analysis of the antigen recognized by this MAB must be carried out to elucidate the molecular nature of the antigen. Anat Rec 254:288-297, 1999. (C) 1999 Wiley-Liss, Inc.