Dorsocross1 (Doc1) encodes a T-box transcription factor of the Tbx6-related subfamily, one of three closely related, clustered and functionally redundant paralogs (Doc1, Doc2, Doc3) with identical embryonic expression. Doc proteins bind T-box (GTG-containing) sites in enhancers via the T-box domain and act in the nucleus as activators or repressors of RNA polymerase II target genes. Doc genes are direct targets of high-level Dpp/Screw (BMP) signaling. In the early embryo they are required for differentiation and survival of the extraembryonic amnioserosa and for patterning of the dorsolateral ectoderm. In the dorsal mesoderm they are induced at the intersection of Dpp and Wingless signals and act with Tinman to activate pannier; mutual cross-regulation among Doc, Tinman and Pannier specifies cardiac progenitors, and Doc is required for all myocardial and most pericardial cells. Later Doc is re-expressed in a segmental subset of cardioblasts (restricted by Tinman) that form the ostia (inflow valves), where Doc activates targets such as Toll. Doc genes also function in wing disc primordium formation, anterior Malpighian tubule budding, and as Dpp mediators in leading-edge cells during pupal thorax closure.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000785 chromatin | IBA GO_REF:0000033 | ACCEPT | Summary: Phylogenetic inference that T-box factors act at chromatin. Reason: Doc1 binds T-box sites in enhancers (Toll, reaper) in vitro and regulates them in vivo; activity at chromatin is expected for a sequence-specific TF. Supporting Evidence: PMID:15870289 DNase I protection assays were used to demonstrate the in vitro binding of Doc1 and Doc2 to the Toll 305-bp dorsal vessel enhancer PMID:19282966 Finally, we identified unknown DNA binding sequences for the assisting factors Doc1 and Disco |
| GO:0000977 RNA polymerase II transcription regulatory region sequence-specific DNA binding | IDA PMID:19282966 Multifactorial regulation of a hox target gene. | ACCEPT | Summary: EMSAs identified a Doc1 binding site in the reaper (rpr) Hox response element; mutating it caused ectopic reporter expression in the maxillary segment. Reason: Direct sequence-specific binding to a Pol II gene regulatory region with in vivo functional validation. Supporting Evidence: PMID:19282966 Finally, we identified unknown DNA binding sequences for the assisting factors Doc1 and Disco PMID:19282966 whereas Brinker (Brk), Disco, Dorsocross 1 (Doc1), En and Slp1 repressed lacZ expression |
| GO:0000978 RNA polymerase II cis-regulatory region sequence-specific DNA binding | IBA GO_REF:0000033 | ACCEPT | Summary: Phylogenetic inference that Doc1, a Tbx6-subfamily T-box protein, binds Pol II cis-regulatory sequences. Reason: Supported directly for Doc1: DNase I footprinting on the Toll dorsal vessel enhancer and EMSA on the reaper enhancer. Supporting Evidence: PMID:15870289 DNase I protection assays were used to demonstrate the in vitro binding of Doc1 and Doc2 to the Toll 305-bp dorsal vessel enhancer PMID:19282966 Finally, we identified unknown DNA binding sequences for the assisting factors Doc1 and Disco |
| GO:0000978 RNA polymerase II cis-regulatory region sequence-specific DNA binding | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro T-box domain mapping to Pol II cis-regulatory region sequence-specific DNA binding. Reason: Consistent with experimental data on Doc1 enhancer binding. Supporting Evidence: PMID:15870289 DNase I protection assays were used to demonstrate the in vitro binding of Doc1 and Doc2 to the Toll 305-bp dorsal vessel enhancer PMID:12783790 The Dorsocross genes encode closely related proteins of the T-box domain family of transcription factors |
| GO:0000981 DNA-binding transcription factor activity, RNA polymerase II-specific | IBA GO_REF:0000033 | ACCEPT | Summary: Phylogenetic inference of Pol II-specific DNA-binding transcription factor activity for T-box proteins. Reason: Core molecular function; Doc1 binds T-box sites and activates (Toll, pannier) or represses (reaper) target enhancers. Supporting Evidence: PMID:15870289 DNase I protection assays were used to demonstrate the in vitro binding of Doc1 and Doc2 to the Toll 305-bp dorsal vessel enhancer PMID:15870289 These findings convincingly support the model of Doc and Tin being positive transcriptional regulators of the Toll dorsal vessel enhancer PMID:12783790 The Dorsocross genes encode closely related proteins of the T-box domain family of transcription factors |
| GO:0000981 DNA-binding transcription factor activity, RNA polymerase II-specific | IDA PMID:15870289 Expression, regulation, and requirement of the toll transmem... | ACCEPT | Summary: Doc1 and Doc2 (full-length or T-box domain) footprint the Toll dorsal vessel enhancer; adding back the Doc-A T-box sites restores enhancer activity in Doc-expressing cardioblasts. Reason: Direct binding plus in vivo enhancer dependence on Doc sites establishes sequence-specific TF activity. Supporting Evidence: PMID:15870289 DNase I protection assays were used to demonstrate the in vitro binding of Doc1 and Doc2 to the Toll 305-bp dorsal vessel enhancer PMID:15870289 These findings convincingly support the model of Doc and Tin being positive transcriptional regulators of the Toll dorsal vessel enhancer PMID:15870289 Systematically adding back T-box core binding elements to partially, then fully, reestablish the Doc-A binding site restores enhancer function in the Svp/Doc population |
| GO:0001700 embryonic development via the syncytial blastoderm | IMP PMID:14732398 Drosophila Tbx6-related gene, Dorsocross, mediates high leve... | MODIFY | Summary: RNAi against the Doc genes disrupts development of the amnioserosa and wing disc primordium, both dependent on high BMP signaling. Reason: 'Embryonic development via the syncytial blastoderm' is a near-root term for insect embryogenesis and is uninformative. The specific phenotypes are in amnioserosa (loss of differentiation and survival, shown also with deficiency mutants) and wing disc primordium (separately annotated to GO:0035294). Amnioserosa maintenance captures the amnioserosa role. Proposed replacements: amnioserosa maintenance Supporting Evidence: PMID:14732398 Inactivation of Doc genes with RNAi dramatically affected the development of amnioserosa and wing disc primordia, both of which depend on high levels of BMP signaling PMID:12783790 Dorsocross gene activity is crucial for the completion of differentiation, cell proliferation arrest, and survival of amnioserosa cells |
| GO:0001708 cell fate specification | IBA GO_REF:0000033 | ACCEPT | Summary: Phylogenetic inference that T-box factors act in cell fate specification. Reason: Doc genes specify cardiac progenitors (with tinman and pannier) and later the ostial cardioblast fate; general but correct. Supporting Evidence: PMID:16221729 co-expression of these three genes in the cardiac mesoderm, which also involves cross-regulation, plays a major role in the specification of cardiac progenitors PMID:16221729 the Dorsocross genes are re-expressed in a segmental subset of cardioblasts, which in the heart region develop into inflow valves (ostia) |
| GO:0003677 DNA binding | IEA GO_REF:0000104 | ACCEPT | Summary: Generic DNA binding from sequence-feature transfer. Reason: Correct parent of the sequence-specific terms; not informative alone. Supporting Evidence: PMID:15870289 DNase I protection assays were used to demonstrate the in vitro binding of Doc1 and Doc2 to the Toll 305-bp dorsal vessel enhancer |
| GO:0003700 DNA-binding transcription factor activity | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro-based DNA-binding transcription factor activity. Reason: Correct general parent of GO:0000981. Supporting Evidence: PMID:12783790 The Dorsocross genes encode closely related proteins of the T-box domain family of transcription factors |
| GO:0005634 nucleus | IBA GO_REF:0000033 | ACCEPT | Summary: Phylogenetic inference of nuclear activity. Reason: Expected for a T-box transcription factor. Supporting Evidence: PMID:12783790 The Dorsocross genes encode closely related proteins of the T-box domain family of transcription factors |
| GO:0005634 nucleus | IEA GO_REF:0000120 | ACCEPT | Summary: Combined automated annotation to nucleus. Reason: Consistent with TF function. Supporting Evidence: PMID:12783790 The Dorsocross genes encode closely related proteins of the T-box domain family of transcription factors |
| GO:0006355 regulation of DNA-templated transcription | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro-based regulation of DNA-templated transcription. Reason: Correct general process. Supporting Evidence: PMID:15870289 These findings convincingly support the model of Doc and Tin being positive transcriptional regulators of the Toll dorsal vessel enhancer |
| GO:0006357 regulation of transcription by RNA polymerase II | IBA GO_REF:0000033 | ACCEPT | Summary: Phylogenetic inference of regulation of Pol II transcription. Reason: Doc1 both activates (Toll, pannier) and represses (reaper) Pol II target genes, so the bidirectional parent term is appropriate. Supporting Evidence: PMID:15870289 These findings convincingly support the model of Doc and Tin being positive transcriptional regulators of the Toll dorsal vessel enhancer PMID:19282966 whereas Brinker (Brk), Disco, Dorsocross 1 (Doc1), En and Slp1 repressed lacZ expression |
| GO:0006357 regulation of transcription by RNA polymerase II | IEA GO_REF:0000117 | ACCEPT | Summary: ARBA machine-learning assignment of regulation of Pol II transcription. Reason: Consistent with experimental data. Supporting Evidence: PMID:15870289 These findings convincingly support the model of Doc and Tin being positive transcriptional regulators of the Toll dorsal vessel enhancer |
| GO:0007507 heart development | TAS PMID:12837580 Establishing A-P polarity in the embryonic heart tube: a con... | ACCEPT | Summary: Traceable author statement from a review on Hox genes and A-P polarity of the dorsal vessel. Reason: The cited review's abstract does not mention Dorsocross, but the role of Doc in heart development is firmly established by primary data (required for all myocardial and most pericardial cells; ostia specification). Accepted as a correct, general process annotation. Supporting Evidence: PMID:16221729 Dorsocross activity is required for the formation of all myocardial and pericardial cell types, with the exception of the Eve-positive pericardial cells PMID:16221729 the Dorsocross genes are re-expressed in a segmental subset of cardioblasts, which in the heart region develop into inflow valves (ostia) PMID:28057263 we provide an overview on the functions of the three Dorsocross paralogs (Doc1-3) and the two Tbx20-related paralogs (midline and H15) during Drosophila heart development |
| GO:0010468 regulation of gene expression | IMP PMID:19282966 Multifactorial regulation of a hox target gene. | MODIFY | Summary: Doc1 is one of several cofactors required with Deformed for correct, localized reaper expression; Doc1 represses the rpr Hox response element through a direct binding site. Reason: Regulation of gene expression is too general; the data show that Doc1 represses Pol II transcription of reaper via a mapped binding site (mis-expression represses, binding-site mutation derepresses). Proposed replacements: negative regulation of transcription by RNA polymerase II Supporting Evidence: PMID:19282966 whereas Brinker (Brk), Disco, Dorsocross 1 (Doc1), En and Slp1 repressed lacZ expression PMID:19282966 We have shown that eight transcriptional regulators, Apt, Gcm, Ems, En, Slp1, Brk, Doc1 and Disco, are required in addition to the Hox protein Dfd to properly regulate the expression of the apoptosis gene reaper |
| GO:0035051 cardiocyte differentiation | IMP PMID:16221729 The Dorsocross T-box genes are key components of the regulat... | ACCEPT | Summary: Dorsocross deficiency mutants lack all myocardial and most pericardial cells; Doc acts with Tinman to activate pannier in cardiac mesoderm. Reason: Core cardiogenic role (shared redundantly by Doc1, Doc2 and Doc3). Supporting Evidence: PMID:16221729 Dorsocross activity is required for the formation of all myocardial and pericardial cell types, with the exception of the Eve-positive pericardial cells PMID:16221729 the Dorsocross genes act in parallel with tinman to activate the expression of pannier, a cardiogenic gene encoding a Gata factor PMID:16221729 co-expression of these three genes in the cardiac mesoderm, which also involves cross-regulation, plays a major role in the specification of cardiac progenitors |
| GO:0035294 determination of wing disc primordium | IMP PMID:14732398 Drosophila Tbx6-related gene, Dorsocross, mediates high leve... | KEEP AS NON CORE | Summary: RNAi against the Doc genes disrupts formation of the wing disc primordium, which depends on high BMP signaling. Reason: Experimental support (RNAi of the redundant Doc genes), but a secondary Dpp-dependent ectodermal role relative to the cardiac and amnioserosa functions. Supporting Evidence: PMID:14732398 Inactivation of Doc genes with RNAi dramatically affected the development of amnioserosa and wing disc primordia, both of which depend on high levels of BMP signaling |
| GO:0045893 positive regulation of DNA-templated transcription | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro-based positive regulation of DNA-templated transcription. Reason: Doc activates Toll and pannier. Supporting Evidence: PMID:15870289 These findings convincingly support the model of Doc and Tin being positive transcriptional regulators of the Toll dorsal vessel enhancer PMID:16221729 the Dorsocross genes act in parallel with tinman to activate the expression of pannier, a cardiogenic gene encoding a Gata factor |
| GO:0045944 positive regulation of transcription by RNA polymerase II | IMP PMID:16221729 The Dorsocross T-box genes are key components of the regulat... | ACCEPT | Summary: Doc genes, in parallel with tinman, are required to activate pannier in cardiac mesoderm. Reason: Consistent with Doc acting as a transcriptional activator of cardiac genes (pannier, Toll). Supporting Evidence: PMID:16221729 the Dorsocross genes act in parallel with tinman to activate the expression of pannier, a cardiogenic gene encoding a Gata factor PMID:15870289 These findings convincingly support the model of Doc and Tin being positive transcriptional regulators of the Toll dorsal vessel enhancer |
| GO:0046529 imaginal disc fusion, thorax closure | IMP PMID:35562934 The Tbx6 Transcription Factor Dorsocross Mediates Dpp Signal... | KEEP AS NON CORE | Summary: Doc is a Dpp target in leading-edge cells of the notum, and Doc knockdown causes a thorax closure defect. Reason: Doc acts upstream of thorax closure as a transcriptional mediator of Dpp in leading-edge cells; a secondary, pupal role. Supporting Evidence: PMID:35562934 Reduction of Doc in the notum region results in a thorax closure defect, similar to that in dpp loss-of-function flies PMID:35562934 we report the identification of T-box transcription factor genes Dorsocross (Doc) as Decapentaplegic (Dpp) targets in the leading edge cells of the notum |
| GO:0061327 anterior Malpighian tubule development | IMP PMID:17190812 Genetic regulation of patterned tubular branching in Drosoph... | KEEP AS NON CORE | Summary: Doc genes, induced by high TGF-beta (Dpp) signaling, are required for budding of the anterior pair of Malpighian tubules. Reason: Valid experimental annotation (deficiency removing all three Doc genes) describing a secondary developmental role. Supporting Evidence: PMID:17190812 We have identified transcriptional regulators specific to and required for anterior (Doc) and posterior (Brk) tubule budding and development PMID:17190812 High levels of TGF-Ξ² promote the expression of Dorsocross1β3 and anterior tubule growth |
| GO:0160108 animal gross anatomical part developmental process | IEA GO_REF:0000117 | MARK AS OVER ANNOTATED | Summary: ARBA assignment to the very general 'animal gross anatomical part developmental process'. Reason: Not wrong but uninformative: more specific developmental processes (heart, amnioserosa, wing disc primordium, Malpighian tubule) are already annotated with experimental evidence. Supporting Evidence: PMID:16221729 Dorsocross activity is required for the formation of all myocardial and pericardial cell types, with the exception of the Eve-positive pericardial cells |
| GO:0046665 amnioserosa maintenance | IMP PMID:12783790 The T-box-encoding Dorsocross genes function in amnioserosa ... | NEW | Summary: Mutants lacking all three Dorsocross genes fail to complete amnioserosa differentiation, do not arrest proliferation and lose amnioserosa cells prematurely. Reason: Genetic evidence that the Doc genes collectively (a deficiency removing Doc1, Doc2 and Doc3, plus RNAi against the Doc genes), acting as Dpp-induced transcription factors in the amnioserosa, are required for its differentiation and survival. As for the cardiac role, the function is shared redundantly by Doc1, Doc2 and Doc3 and has not been shown for Doc1 alone. No amnioserosa term is currently annotated. Supporting Evidence: PMID:12783790 Dorsocross gene activity is crucial for the completion of differentiation, cell proliferation arrest, and survival of amnioserosa cells PMID:14732398 Inactivation of Doc genes with RNAi dramatically affected the development of amnioserosa and wing disc primordia, both of which depend on high levels of BMP signaling |
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Download this section (compressed HTML)Q: Given the complete redundancy of Doc1, Doc2 and Doc3, which loss-of-function annotations derived from deficiencies removing all three genes should be propagated equally to each paralog?
Q: Does Doc physically interact with Tinman or Pannier on shared cardiac enhancers, as TBX5 does with NKX2-5 and GATA4 in vertebrates?
Q: Is there a GO term suitable for specification of the ostial (inflow valve) cardioblast fate in arthropod hearts?
Experiment: Single-paralog CRISPR nulls of Doc1, Doc2 and Doc3 to test whether any paralog has a non-redundant function in heart or amnioserosa development.
Experiment: Co-immunoprecipitation and ChIP/CUT&RUN of Doc with Tinman and Pannier in embryonic cardiac mesoderm to test for a physical cardiogenic complex.
Dorsocross1 (Doc1) encodes one of the three tissue-specific T-box transcription factors encoded by the Dorsocross cluster. It is crucial for completion of differentiation, cell proliferation arrest and survival of amnioserosa cells, as well as for cardiogenesis and the patterning and morphogenesis of particular ectodermal derivatives.
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