dev, FGFR, DFR2, DFGF-R1, FGF receptor
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Gene model reviewed during 5.46
4.3 (northern blot)
Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\btl using the Feature Mapper tool.
Comment: expression is lower in adults than earlier stages
Expression pattern inferred from unspecified enhancer trap line.
Transcript is detected in the 10 ectodermal placodes that specify the trachea. Expression begins a short time after the trh protein is first detected in this region.
btl transcripts first become detectable in tracheal placodes at stage 10 and reach maximal levels by stage 11. At stage 12, six major buds grow out in different directions. It was observed that transverse connectives and primary branches not giving off secondary and terminal branches lose btl expression at earlier stages while primary branches from which secondary and terminal branches are given off appear to continue to express btl until later stages.
btl expression is first observed in the anterior and posterior midgut primordia at the beginning of germ band extension. The expression becomes more prominent when the midguts invaginate. At stage 8, expression is observed along the ventral midline. By stage 10, expression is observed in cells contributing to tracheal pit formation. Finally, at stage 13, btl expression is observed in cells corresponding to presumptive salivary ducts and salivary tubes.
btl expression is detected just before the onset of gastrulation at stage 5 at the posterior pole and in two groups of ventral cells at the anterior tip of the embryo. During gastrulation, btl expression is detected in the mesectodermal precursor cells as they migrate toward the midline, where they meet to form the midline precursor cells. Expression continues in the midline cells and becomes modulated in a segmental manner. During stage 12, btl expression is most pronounced in the midline cells in the posterior half of each segment. This includes the VUM neurons and the posterior pair of midline glial cells.
Expression in the midline and tracheal pits was observed at about 10% of wild type levels.
Only trace amounts of btl transcripts are detected.
btl transcripts are expressed throughout development with maximal levels in 0-12hr embryos. They are detected in the cells surrounding the developing tracheal pits in germ band extended embryos.
bnl protein is expressed in two bowl-like sets of cells in the A9 primordium of the male genital discs of third instar larvae.
Comment: heat-shock dependent
GBrowse - Visual display of RNA-Seq signals
View Dmel\btl in GBrowse 2Please Note FlyBase no longer curates genomic clone accessions so this list may not be complete
Please Note This section lists cDNAs and ESTs that fall within the genomic extent of the gene model, which may include cDNAs and ESTs of genes within introns, or of overlapping genes. Please see GBrowse for alignment of the cDNAs and ESTs to the gene model.
For each fully sequenced cDNA the DGRC maintains various forms of the cDNA (e.g tagged or untagged) in several different host vectors for subsequent cloning and expression in Drosophila and Drosophila cell lines.
polyclonal
Source for merge of: btl dev
Source for merge of: dev l(3)j2E11
l(3)L0499 may correspond to btl: the P{lacW}l(3)L0499L0499 insertion maps within the transcription unit.
Identified by PCR fragment; relationship to other protein tyrosine kinase genes not known.
btl is required during tracheal branching morphogenesis. A cell at the branch tip requires btl and leads outgrowth. Trailing cells do not require btl. There appears to be competition (involving N-mediated lateral inhibition) between tracheal cells, such that those with the highest btl activity take the lead position at the branch tip and those with less btl activity assume subsidiary positions and form the branch stalk.
One of 42 Drosophila genes identified as being most likely to reveal molecular and cellular mechanisms of nervous system development or plasticity relevant to human Mental Retardation disorders.
dsRNA made from templates generated with primers directed against this gene tested in RNAi screen for effects on Kc167 and S2R+ cell morphology.
Phylogenetic analysis of the PTK family.
The btl FGF receptor, required for primary tracheal branching, is also required to activate expression of markers involved in secondary branching.
btl is obligatory primarily for the onset of the tracheal migration process and is also required for the formation of tracheoles.
The normal activity of btl in promoting cell migration does not require spatially restricted cues.
Disruption of the trachea, using overlapping deletions that remove btl abolishes the ability of the intersegmental nerve to extend through the lateral part of the embryo.
Mutations at btl affect tracheal development, and migration of posterior pair of midline glial cells to posterior commisure.
Associated with recessive larval lethality.
The btl gene product participates in receiving spatial clues that guide tracheal cell outgrowth.
Isolation: as a dominant suppressor of Pc mutations.
Kennison, 1983.
