Biomaterial Database

Xenopus Distal-less related homeobox genes are expressed in the developing forebrain and are induced by planar signals. 1993

N Papalopulu, and C Kintner

Molecular Neurobiology Laboratory, Salk Institute, La Jolla, CA 92037.

The polymerase chain reaction (PCR) was used to isolated five Xenopus homeobox clones (X-dll1 to 5) that are related to the Drosophila Distal-less (Dll) gene and we propose a subdivision of the vertebrate distal-less gene family according to sequence similarities. cDNA clones were isolated for X-dll2, 3 and 4, and their expression was studied by RNase protection and in situ hybridization. X-dll2, which belongs to a separate subfamily than X-dll3 and 4, is not expressed in the neural ectoderm. X-dll3 and X-dll4, which belong to the same subfamily, have a similar but not identical pattern of expression that is restricted to anterior ectodermal derivatives, namely the ventral forebrain, the cranial neural crest and the cement gland. X-dll3 is also expressed in the olfactory and otic placodes while X-dll4 is expressed in the developing eye. X-dll3 differs from the other Xenopus genes and the previously isolated Dll-related mouse genes, in that localized expression can be detected by in situ hybridization very early in development, in the anterior-transverse ridge of the open neural plate. Based on that early expression pattern, we suggest that X-dll3 marks the rostral-most part of the neural plate, which gives rise to the ventral forebrain. Finally, we have used these Xenopus distal-less genes to show that the anterior neural plate can be induced by signals that spread within the plane of neural ectoderm, indicating that at least the initial steps of forebrain development do not require signals from underlying mesoderm.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D005801	Genes, Homeobox	Genes that encode highly conserved TRANSCRIPTION FACTORS that control positional identity of cells (BODY PATTERNING) and MORPHOGENESIS throughout development. Their sequences contain a 180 nucleotide sequence designated the homeobox, so called because mutations of these genes often results in homeotic transformations, in which one body structure replaces another. The proteins encoded by homeobox genes are called HOMEODOMAIN PROTEINS.	Genes, Homeotic,Homeobox Sequence,Homeotic Genes,Genes, Homeo Box,Homeo Box,Homeo Box Sequence,Homeo Boxes,Homeobox,Homeoboxes,Hox Genes,Sequence, Homeo Box,Gene, Homeo Box,Gene, Homeobox,Gene, Homeotic,Gene, Hox,Genes, Hox,Homeo Box Gene,Homeo Box Genes,Homeo Box Sequences,Homeobox Gene,Homeobox Genes,Homeobox Sequences,Homeotic Gene,Hox Gene,Sequence, Homeobox,Sequences, Homeo Box,Sequences, Homeobox
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014982	Xenopus laevis	The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.	Platanna,X. laevis,Platannas,X. laevi
D015870	Gene Expression	The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.	Expression, Gene,Expressions, Gene,Gene Expressions
D016133	Polymerase Chain Reaction	In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.	Anchored PCR,Inverse PCR,Nested PCR,PCR,Anchored Polymerase Chain Reaction,Inverse Polymerase Chain Reaction,Nested Polymerase Chain Reaction,PCR, Anchored,PCR, Inverse,PCR, Nested,Polymerase Chain Reactions,Reaction, Polymerase Chain,Reactions, Polymerase Chain
D016415	Sequence Alignment	The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.	Sequence Homology Determination,Determination, Sequence Homology,Alignment, Sequence,Alignments, Sequence,Determinations, Sequence Homology,Sequence Alignments,Sequence Homology Determinations
D016548	Prosencephalon	The anterior of the three primitive cerebral vesicles of the embryonic brain arising from the NEURAL TUBE. It subdivides to form DIENCEPHALON and TELENCEPHALON. (Stedmans Medical Dictionary, 27th ed)	Forebrain,Forebrains
D017403	In Situ Hybridization	A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.	Hybridization in Situ,Hybridization, In Situ,Hybridizations, In Situ,In Situ Hybridizations