Xenopus hand2 expression marks anterior vascular progenitors but not the developing heart

Smith, Stuart J.; Kotecha, Surendra; Towers, Norma; Mohun, Timothy J.

doi:10.1002/1097-0177(200012)219:4<575::aid-dvdy1075>3.0.co;2-y

Cited by 11 publications

(12 citation statements)

References 29 publications

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“…2K and N). This punctuate pattern is similar to that of Xphox2A and XHand2 and has been suggested to be progenitors of smooth muscle cells or pericytes of the forming vasculature (Smith et al, 2000;Talikka et al, 2004). Interestingly, we have also observed a similar punctuate expression by other proneural genes such as X-MyT1 (data not shown) and N-tubulin (Fig 2P) suggesting they are neuronal cells.…”

supporting

confidence: 85%

Expression and regulation of Xenopus CRMP-4 in the developing nervous system

Souopgui¹,

Klisch²,

Pieler³

et al. 2007

Int. J. Dev. Biol.

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KEY WORDS: Xenopus, primary neurogenesis, neurogenin, CRMP, NotchThe collapsin response mediator proteins (CRMPs) (also known as TOAD (turned on after division), Ulip (unc-33 like protein) and DRP (dihydropyrimidinase family) are a conserved family of cytosolic phosphoproteins highly expressed in the nervous system (Wang and Strittmatter, 1996). Even though the CRMPs exhibit more than 60% amino acid identity to the amidohydrolase family, they do not possess enzymatic activity (Wang and Strittmatter, 1997).The first CRMP was identified as an intracellular mediator of semaphorin/collapsin growth cone collapse (Goshima et al., 1995). However, numerous studies have demonstrated that the activities of CRMPs are not restricted to this repulsive guidance cue and participate in a broad spectrum of additional activities, with function being dependant on the specific interaction with various protein partners (Arimura et al., 2004). CRMP-2 participates in LPA-induced growth cone collapse and regulates axonogenesis through the binding of tubulin heterodimers (Inagaki et al., 2001;Fukata et al., 2002). CRMP-2 also contributes to the establishment of neuronal polarity through the association with Numb and promoting Numb-mediated endocytosis of the neuronal cell adhesion molecule L1 (Nishimura et al., 2003).Int. J. Dev. Biol. 51: 339-343 (2007) CRMP proteins are also targets of a variety of protein kinases. CRMP-2 and CRMP-4 were identified as brain-specific substrates for glycogen synthase kinase 3 (GSK3) and during growth cone collapse, phosphorylation by Rho-associated kinase inhibits microtubule assembly and Numb-mediated endoyctosis Yoshimura et al., 2005;Cole et al., 2006). Recently, CRMP-2 was identified as a negative regulator of p53 and it has been suggested to play a role in the regulation of proliferation (Llanos et al., 2006;Tahimic et al., 2006). Moreover, the CRMPs may contribute to the pathogenesis of specific neurodegenerative disorders (Charrier et al., 2003).Presently, we describe the expression analysis of CRMP-4, during early Xenopus embryogenesis. CRMP-4 is expressed in the differentiating primary neurons and later expression is maintained throughout the central nervous system and in the eye. Correspondingly, CRMP-4 is positively regulated by X-ngnr-1 and negatively regulated by the Notch pathway. Results and DiscussionXenopus CRMP-4 was identified in a microarray screen aimed at identifying genes induced in dissociated ectodermal explants by the neuronal determination transcription factor, X-ngnr-1. Comparison of the predicted amino acid sequence revealed Xenopus CRMP-4 is 90% identical to the corresponding human and mouse sequences. Lower identity was observed between Xenopus CRMP-2 (75%) and other mammalian CRMP members (71-74%) (Fig. 1). The Cdk5 priming and GSK3 phosphorylation sites identified in the mammalian CRMP-2 are conserved (Uchida et al., 2005;Yoshimura et al., 2005).The expression of CRMP-4 during early Xenopus embryogenesis was investigated by RT-PCR analysis with RNA isolated from var...

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supporting

confidence: 85%

Expression and regulation of Xenopus CRMP-4 in the developing nervous system

Souopgui¹,

Klisch²,

Pieler³

et al. 2007

Int. J. Dev. Biol.

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“…In Xenopus, it is specifically expressed in the ventral part of all branchial arches (Smith et al, 2000). In 5-HT2B-overexpressing embryos, XHand2 was ectopically expressed in the dorsal part of posterior branchial arches, to which the ectopic cartilage was often fused.…”

Section: -Ht2b Gain-of-function Results In Ectopic Xbap and Xhand2 Ementioning

confidence: 99%

“…Digoxigenin (DIG) (Roche) labeled antisense RNA probes were generated for 5-HT2B (De Lucchini et al, 2003), Xbap (Newmann et al, 1997), XHoxa2 (Pasqualetti et al, 2000), XDll4 (Papalopulu and Kintner, 1993), XEphrinB2 (Smith et al, 1997), XHand2 (Smith et al, 2000), XMel1 (Van Campenhout et al, 2006), XSlug (Mayor et al, 1995) and XSox9 (Spokony et al, 2002). Fluorescein (FLUO) (Roche) labeled antisense RNA probes were also generated for XSox9 and XHand2 in order to perform double ISH experiments.…”

Section: In Situ Hybridization (Ish) Experimentsmentioning

confidence: 99%

Serotonin 2B receptor signaling is required for craniofacial morphogenesis and jaw joint formation in Xenopus

et al. 2010

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SUMMARYSerotonin (5-HT) is a neuromodulator that plays many different roles in adult and embryonic life. Among the 5-HT receptors, 5-HT2B is one of the key mediators of 5-HT functions during development. We used Xenopus laevis as a model system to further investigate the role of 5-HT2B in embryogenesis, focusing on craniofacial development. By means of gene gain-and loss-offunction approaches and tissue transplantation assays, we demonstrated that 5-HT2B modulates, in a cell-autonomous manner, postmigratory skeletogenic cranial neural crest cell (NCC) behavior without altering early steps of cranial NCC development and migration. 5-HT2B overexpression induced the formation of an ectopic visceral skeletal element and altered the dorsoventral patterning of the branchial arches. Loss-of-function experiments revealed that 5-HT2B signaling is necessary for jaw joint formation and for shaping the mandibular arch skeletal elements. In particular, 5-HT2B signaling is required to define and sustain the Xbap expression necessary for jaw joint formation. To shed light on the molecular identity of the transduction pathway acting downstream of 5-HT2B, we analyzed the function of phospholipase C beta 3 (PLC) in Xenopus development and showed that PLC is the effector of 5-HT2B during craniofacial development. Our results unveiled an unsuspected role of 5-HT2B in craniofacial development and contribute to our understanding of the interactive network of patterning signals that is involved in the development and evolution of the vertebrate mandibular arch.

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“…Briefly, 3-5 l of 35 S-labeled MEF2 and E47 proteins were incubated with 300 ng of immobilized HAND1 fusion proteins in 500 l of IpH buffer (50 mM Tris, pH 8.0, 150 mM NaCl, 5 mM EDTA, 0.1% Nonidet P-40, 1 mM dithiothreitol, 0.5 mM phenylmethylsulfonyl fluoride, 0.25% bovine serum albumin (BSA)) for 2 h at 4°C with agitation and then centrifuged for 2 min at 1500 rpm at 4°C. The amount of total 35 S-labeled proteins was kept constant (8 l) in each binding reaction by adding 35 S-labeled luciferase to complete. Beads were washed three times by vortexing in 500 l of IpH buffer without BSA.…”

Section: Methodsmentioning

confidence: 99%

“…4A), suggesting physical interaction between the two proteins. To determine whether this interaction was direct, we performed in vitro pull-down assays using immobilized GST-HAND1 and in vitro translated 35 S-labeled MEF2 proteins. E47 was included as positive control.…”

Section: Hand1 Is a Transcriptional Activator Of Anf-to Test Whether Anfmentioning

confidence: 99%

MEF2-dependent Recruitment of the HAND1 Transcription Factor Results in Synergistic Activation of Target Promoters

Morin

Pozzulo

Robitaille

et al. 2005

Journal of Biological Chemistry

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HAND proteins are tissue-restricted members of the basic helixloop-helix transcription factor family that play critical roles in cell differentiation and organogenesis including placental, cardiovascular, and craniofacial development. Nevertheless, the molecular basis underlying the developmental action of HAND proteins remains undefined. Within the embryo, HAND1 is first detected in the developing heart where it becomes restricted to the atrial and left ventricular compartments, a pattern identical to that of the Nppa gene, which encodes atrial natriuretic factor, the major secretory product of the heart. We hereby report that the cardiac atrial natriuretic factor promoter is directly activated by HAND1, making it the first known HAND1 transcriptional target. The action of HAND1 does not require heterodimerization with class I basic helix-loop-helix factors or DNA binding through E-box elements. Instead, HAND1 is recruited to the promoter via physical interaction with MEF2 proteins. MEF2/HAND1 interaction results in synergistic activation of MEF2-dependent promoters, and MEF2 binding sites are sufficient to mediate this synergy. MEF2 binding to DNA is not enhanced in the presence of HAND1. Instead, cooperativity likely results from corecruitment of co-activators such as CREB-binding protein. The related HAND2 protein can also synergize with MEF2. Thus, HAND proteins act as cell-specific developmental co-activators of the MEF2 family of transcription factors. These findings identify a novel mechanism for HAND action in the heart and provide a general paradigm to understand the mechanism of HAND action in organogenesis.

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Xenopus hand2 expression marks anterior vascular progenitors but not the developing heart

Cited by 11 publications

References 29 publications

Expression and regulation of Xenopus CRMP-4 in the developing nervous system

Expression and regulation of Xenopus CRMP-4 in the developing nervous system

Serotonin 2B receptor signaling is required for craniofacial morphogenesis and jaw joint formation in Xenopus

MEF2-dependent Recruitment of the HAND1 Transcription Factor Results in Synergistic Activation of Target Promoters

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