title: Expression of an amphibian homolog of the Eph family of receptor tyrosine kinases is developmentally regulated.
abstract: In order to study the function of tyrosine kinase receptors during Xenopus development, we have isolated Xek (Xenopus Elk-like kinase), a tyrosine kinase receptor, which shows significant homology to rat Elk and chicken cek5, members of the Eph family. Xek exists as a maternally expressed mRNA which decreases in expression at the mid blastula transition and reappears at late neurulation in Xenopus. Xek mRNA is expressed at higher levels in the anterior and dorsal regions of embryonic stages 16, 24 and 37. In adult Xenopus tissues, Xek appears to be ubiquitously expressed with higher expression observed in brain and ovary. In situ hybridization analysis demonstrates localized mRNA expression in the brain, brachial arches, trigeminal facial ganglion, and the retina of the swimming tadpole stage of development. The similarities in sequence and expression pattern suggest that Xek is an amphibian member of the Eph family and may play a role in the development or function of the central nervous system.
authors.affiliation: Laboratory of Leukocyte Biology, National Cancer Institute-Frederick Cancer Research and Development Center, Maryland 21702.
authors.forename: T L
authors.initials: TL
authors.lastname: Jones
authors.forename: I
authors.initials: I
authors.lastname: Karavanova
authors.forename: M
authors.initials: M
authors.lastname: Maéno
authors.forename: R C
authors.initials: RC
authors.lastname: Ong
authors.forename: H F
authors.initials: HF
authors.lastname: Kung
authors.forename: I O
authors.initials: IO
authors.lastname: Daar
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002645:Chickens; D017931:DNA Primers; D018507:Gene Expression Regulation, Developmental; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D036143:Receptor, EphA8; D017386:Sequence Homology, Amino Acid; D014982:Xenopus laevis
chemical_list: D017931:DNA Primers; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D020794:Receptor Protein-Tyrosine Kinases; D036143:Receptor, EphA8