Expression of Xenopus laevis Lhx2 during eye development and evidence for divergent expression among vertebrates.
Members of the LIM homeodomain (LIM-HD) family of proteins are double zinc-finger containing transcription factors with important functions in pattern formation and cell lineage determination. The LIM-HD family member Lhx2 is required for normal eye, liver, and central nervous system formation. Lhx2(-/-) mice lack eyes, and experiments in Xenopus predict that Lhx2 forms a regulatory network with other eye field transcription factors to specify the eye field during eye formation. Here, we describe the structure and developmental expression pattern of the Xenopus laevis homologue, XLhx2. We show that XLhx2 shares significant amino acid sequence identity with other vertebrate Lhx2 proteins and Drosophila apterous (ap). The expression patterns of XLhx2 in the early neural plate and during eye development are consistent with a role in eye field specification and retinal differentiation. Despite highly similar expression patterns in the mouse and Xenopus central nervous system, divergent expression patterns were also observed. Phylogenetic analysis confirmed the identity of the isolated cDNA as a Xenopus ortholog of Lhx2. Therefore, in spite of structural similarities, the mouse and Xenopus Lhx2 expression patterns differ, suggesting potential functional differences in these species.
Departments of Ophthalmology and Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
Andrea S
AS
Viczian
Anne G
AG
Bang
William A
WA
Harris
Michael E
ME
Zuber
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005123:Eye / Q000196:embryology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D017403:In Situ Hybridization; D060850:LIM-Homeodomain Proteins; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014714:Vertebrates / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism
D018398:Homeodomain Proteins; C489783:LHX2 protein, human; D060850:LIM-Homeodomain Proteins; D019913:Nuclear Localization Signals; D014157:Transcription Factors; D029867:Xenopus Proteins; D004247:DNA