Characterization and embryonic expression of four amphioxus Frizzled genes with important functions during early embryogenesis

Qian, Guanghui; Li, Guang; Chen, Xiaoying; Wang, Yiquan

doi:10.1016/j.gep.2013.08.003

Cited by 18 publications

(37 citation statements)

References 42 publications

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“…2) (Wang et al, 2016b). Lrp5/6,Axin,Gsk3b,APC,Gro,Ckla,Ckl3b,and (Holland et al, 2005;Kozmikova et al, 2013;Lin et al, 2006;Morov et al, 2016;Onai et al, 2010;Qian et al, 2013;Schubert et al, 2000a;Schubert et al, 2000b;Wang et al, 2016a;Yasui et al, 2002;Yu et al, 2007), and this report (Fig. 5).…”

Section: Maternal Signals In Early Amphioxus Embryossupporting

confidence: 61%

“…Transcript distribution patterns of several components of the canonical Wnt/b-catenin signaling pathway have been recently analyzed using in situ hybridization in fertilized amphioxus eggs (Qian et al, 2013;Wang et al, 2016b). Dvl, which acts directly downstream of the Wnt signaling receptor Frizzled (Fig.…”

Section: Maternal Signals In Early Amphioxus Embryosmentioning

confidence: 99%

“…et al, 2016b), indicating that these components are already present in the unfertilized egg. Additionally, four Frizzled receptors are maternally expressed in amphioxus (Qian et al, 2013). For Wnt ligands, Wnt1, Wnt6, Wnt9, Wnt10, and Wnt11 were shown to be maternally expressed at low levels when they were analyzed using RT-qPCR.…”

Section: Maternal Signals In Early Amphioxus Embryosmentioning

confidence: 99%

“…For Wnt ligands, Wnt1, Wnt6, Wnt9, Wnt10, and Wnt11 were shown to be maternally expressed at low levels when they were analyzed using RT-qPCR. Wnt4 is also likely to be maternally expressed because its transcripts can be detected in 4-cell stage embryos (Qian et al, 2013). On the other hand, the transcripts of Wnt3, Wnt5, Wnt7, and Wnt8 are not detectable prior to the blastula stage, suggesting that they are only expressed zygotically after the blastula stage (Qian et al, 2013).…”

Section: Maternal Signals In Early Amphioxus Embryosmentioning

confidence: 99%

“…The components of the canonical Wnt signaling pathway, including Frizzled, Lrp5/6,Axin,Gsk3b,APC,Gro,Ckla,Ckl3b, and Cklδ, remain ubiquitously expressed until the end of blastulation (Qian et al, 2013;Wang et al, 2016b). Similar to the one-cell stage, the transcripts of Dishevelled and Tcf are asymmetrically distributed toward the animal pole during the cleavage and blastula stages (Fig.…”

Section: Distribution Of Transcripts and The Activity Of Signaling Pamentioning

confidence: 99%

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Dorsal-ventral patterning in amphioxus: current understanding, unresolved issues, and future directions

Kozmiková

Yu²

2017

Int. J. Dev. Biol.

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How the embryonic body axis is generated is a fundamental question in developmental biology. The molecular mechanisms involved in this process have been the subject of intensive studies using traditional model organisms during the last few decades, and the results have provided crucial information for understanding the formation of animal body plans. In particular, studies exploring the molecular nature of Spemann's organizer have revealed the intricate interactions underlying several signaling pathways (namely the Wnt/b-catenin, Nodal and Bmp pathways) that pattern the dorsoventral (DV) axis in vertebrate embryos. Furthermore, recent comparative studies have shown that many of these signaling interactions are also employed in other non-vertebrate model organisms for their early embryonic axis patterning. These results suggest that there is deep homology in DV patterning mechanisms among bilaterian animals and that these mechanisms may be traced back to the common ancestor of cnidarians and bilaterians. However, the mechanism by which the DV axis became inverted in the chordate lineage relative to the DV axis in other bilaterian animals remains unclear. Cephalochordata (i.e., amphioxus) represent a basal chordate group which occupies a key phylogenetic position for explorations of the origin of the chordate body plan. In this review, we summarize what is currently known regarding the developmental mechanisms that establish the DV axis in amphioxus embryos. By comparing this to what is known in vertebrates, we can start to hypothesize about the ancestral DV patterning mechanisms in chordates and discuss their possible evolutionary origins.

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Section: Maternal Signals In Early Amphioxus Embryossupporting

confidence: 61%

Section: Maternal Signals In Early Amphioxus Embryosmentioning

confidence: 99%

Section: Maternal Signals In Early Amphioxus Embryosmentioning

confidence: 99%

Section: Maternal Signals In Early Amphioxus Embryosmentioning

confidence: 99%

Section: Distribution Of Transcripts and The Activity Of Signaling Pamentioning

confidence: 99%

See 3 more Smart Citations

Dorsal-ventral patterning in amphioxus: current understanding, unresolved issues, and future directions

Kozmiková

Yu²

2017

Int. J. Dev. Biol.

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Specification and positioning of the anterior neuroectoderm in deuterostome embryos

Range

2014

Genesis

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Summary: The molecular mechanisms used by deuterostome embryos (vertebrates, urochordates, cephalochordates, hemichordates, and echinoderms) to specify and then position the anterior neuroectoderm (ANE) along the anterior-posterior axis are incompletely understood. Studies in several deuterostome embryos suggest that the ANE is initially specified by an early, broad regulatory state. Then, a posterior-to-anterior wave of respecification restricts this broad ANE potential to the anterior pole. In vertebrates, sea urchins and hemichordates a posterior-anterior gradient of Wnt/b-catenin signaling plays an essential and conserved role in this process. Recent data collected from the basal deuterostome sea urchin embryo suggests that positioning the ANE to the anterior pole involves more than the Wnt/bcatenin pathway, instead relying on the integration of information from the Wnt/b-catenin, Wnt/JNK, and Wnt/ PKC pathways. Moreover, comparison of functional and expression data from the ambulacrarians, invertebrate chordates, and vertebrates strongly suggests that this Wnt network might be an ANE positioning mechanism shared by all deuterostomes. genesis 52:222-234. V C 2014 Wiley Periodicals, Inc.Key words: development; anterior neuroectoderm; evolution; regulatory networks Establishment of the anterior neuroectoderm (ANE) is a defining feature of the animal body plan, yet it is still unclear how this territory is created or how it evolved in deuterostome embryos (vertebrates, urochordates, cephalochordates, hemichordates, and echinoderms; Fig. 1). ANE structures range from the simple bundle of sensory neurons in sea urchin larvae to the complex vertebrate forebrain and eye field. In all deuterostome embryos the ANE starts out as a simple, flat neuroepithelium. In vertebrates this simple neuroepithelium later undergoes complicated molecular patterning and morphogenetic movements that produce the forebrain and eye field, which have made it difficult to fully understand the establishment of this territory. In contrast, there are few cell movements during specification and patterning of the ANE in invertebrate deuterostome embryos (urochordate, cephalochordate, hemichordates, and echinoderms), making these tractable model systems for studying the early gene regulatory networks (GRNs) that establish and position this territory. However, this simplicity has made it challenging to identify morphological homologies between the invertebrate deuterostomes and the vertebrates. Moreover, the ANE is placed at the anterior-dorsal side of chordate embryos, whereas it is generally established around the anterior pole in ambulacrarian embryos (hemichordates and echinoderms), complicating comparisons between these two groups. In spite of these significant morphological differences recent comparative gene expression and functional studies, coupled with high-throughput genome-wide assays, have provided new insight into early neuroectoderm specification and patterning in the invertebrate deuterostomes. These studies show that the GRNs und...

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The role of thePax1/9gene in the early development of amphioxus pharyngeal gill slits

Liu

Xian

et al. 2014

J. Exp. Zool. (Mol. Dev. Evol.)

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The pharynx is a major characteristic of chordates. Compared with vertebrates, amphioxus has an advantage for the study of pharynx development, as embryos lack neural crest, and the pharynx is mainly derived from endoderm cells. The Pax1/9 subfamily genes have essential roles in vertebrate pharyngeal patterning, but it is not known if the Pax1/9 gene has similar functions in amphioxus pharynx development. To answer this question, we examined the Pax1/9 gene expression pattern in amphioxus embryos at different developmental stages, and observed morphological changes following Pax1/9 knockdown. RT-qPCR analysis indicated that Pax1/9 expression was initiated during early neurula stage and rapidly peaked during mid-neurula stage. Furthermore, in situ hybridization analysis showed that Pax1/9 transcripts were localized exclusively in the most endodermal region of the developing pharynx in early neurula stage embryos; however, Pax1/9 expression was strikingly down-regulated in the region where gill slits would form from the fusion of endoderm and ectoderm in subsequent developmental stages and was maintained in the border regions between adjacent gill slits. Knockdown of Pax1/9 function using both morpholino and siRNA approaches led to embryonic defects in the first three gill slits, and fusion of the first two gill slits. Moreover, the expression levels of the pharyngeal marker genes Six1/2 and Tbx1/10 were reduced in Pax1/9 knockdown embryos. From these observations, we concluded that the Pax1/9 gene has an important role in the initial differentiation of amphioxus pharyngeal endoderm and in the formation of gill slits, most likely via modulation of Six1/2 and Tbx1/10 expression.

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Characterization and embryonic expression of four amphioxus Frizzled genes with important functions during early embryogenesis

Cited by 18 publications

References 42 publications

Dorsal-ventral patterning in amphioxus: current understanding, unresolved issues, and future directions

Dorsal-ventral patterning in amphioxus: current understanding, unresolved issues, and future directions

Specification and positioning of the anterior neuroectoderm in deuterostome embryos

The role of thePax1/9gene in the early development of amphioxus pharyngeal gill slits

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