Widespread cloning in echinoderm larvae

Eaves, Alexandra A.; Palmer, A. Richard

doi:10.1038/425146a

Cited by 74 publications

(43 citation statements)

References 11 publications

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“…Under controlled laboratory conditions, the clones have been shown to be able to metamorphose and form normal juveniles (Eaves and Palmer, 2003;Knott et al, 2003). It is not yet known whether hemichordate tornaria larvae also have the ability to clone, but it would be an interesting finding.…”

Section: Bj Swallamentioning

confidence: 96%

“…In addition, it appears that echinoderm larvae have the ability to clone themselves when they are in the plankton for long periods of time (Eaves and Palmer, 2003;Knott et al, 2003). Under controlled laboratory conditions, the clones have been shown to be able to metamorphose and form normal juveniles (Eaves and Palmer, 2003;Knott et al, 2003).…”

Section: Bj Swallamentioning

confidence: 99%

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Building divergent body plans with similar genetic pathways

Swalla

2006

Heredity

108

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Deuterostome animals exhibit widely divergent body plans. Echinoderms have either radial or bilateral symmetry, hemichordates include bilateral enteropneust worms and colonial pterobranchs, and chordates possess a defined dorsal-ventral axis imposed on their anterior-posterior axis. Tunicates are chordates only as larvae, following metamorphosis the adults acquire a body plan unique for the deuterostomes. This paper examines larval and adult body plans in the deuterostomes and discusses two distinct ways of evolving divergent body plans. First, echinoderms and hemichordates have similar feeding larvae, but build a new adult body within or around their larvae. In hemichordates and many direct-developing echinoderms, the adult is built onto the larva, with the larval axes becoming the adult axes and the larval mouth becoming the adult mouth. In contrast, indirect-developing echinoderms undergo radical metamorphosis where adult axes are not the same as larval axes. A second way of evolving a divergent body plan is to become colonial, as seen in hemichordates and tunicates. Early embryonic development and gastrulation are similar in all deuterostomes, but, in chordates, the anterior-posterior axis is established at right angles to the animal-vegetal axis, in contrast to hemichordates and indirect-developing echinoderms. Hox gene sequences and anterior-posterior expression patterns illuminate deuterostome phylogenetic relationships and the evolution of unique adult body plans within monophyletic groups. Many genes that are considered vertebrate 'mesodermal' genes, such as nodal and brachyury T, are likely to ancestrally have been involved in the formation of the mouth and anus, and later were evolutionarily co-opted into mesoderm during vertebrate development.

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Section: Bj Swallamentioning

confidence: 96%

Section: Bj Swallamentioning

confidence: 99%

Building divergent body plans with similar genetic pathways

Swalla

2006

Heredity

108

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“…Goss, 1969;Emson and Wilkie, 1980;Mashanov and García-Arrarás, 2011). Echinoderm larvae can even produce a functional larval clone derived by budding from the original larval body (Bosch et al, 1989;Eaves and Palmer, 2003). Embryos from this phylum are well known for marked regulative development; many cells maintain 'multipotency' and change fates in response to changes in neighbouring cells (Horstadius, 1950(Horstadius, ,1973Ransick and Davidson, 1993;Dubois and Ameye, 2001), including the germ line (Goss, 1969;Emson and Wilkie, 1980;Eaves and Palmer, 2003;Vaughn and Strathmann, 2008;Ransick and Davidson, 1993).…”

Section: Introductionmentioning

confidence: 99%

Essential elements for translation: the germline factor Vasa functions broadly in somatic cells

Yajima

Wessel

2015

Development

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Vasa is a conserved RNA-helicase found in the germ lines of all metazoans tested. Whereas Vasa presence is often indicated as a metric for germline determination in animals, it is also expressed in stem cells of diverse origin. Recent research suggests, however, that Vasa has a much broader function, including a significant role in cell cycle regulation. Results herein indicate that Vasa is utilized widely, and often induced transiently, during development in diverse somatic cells and adult precursor tissues. We identified that Vasa in the sea urchin is essential for: (1) general mRNA translation during embryogenesis, (2) developmental re-programming upon manipulations to the embryo and (3) larval wound healing. We also learned that Vasa interacted with mRNAs in the perinuclear area and at the spindle in an Importin-dependent manner during cell cycle progression. These results suggest that, when present, Vasa functions are essential to contributing to developmental regulation.

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“…The regulatory state of endoderm cells at the gastrula stage is clearly very different from that of NSM cells, and it will be instructive to investigate the changes in GRN architecture that accompany this particular re-specification process. Even more extensive re-wiring of GRNs is likely to underlie skeletogenesis during the remarkable process of larval cloning; i.e., the budding of complete, new individuals from small regions of advanced larvae (Eaves and Palmer, 2003;Vaughn and Strathmann, 2008). …”

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confidence: 99%

Lessons from a gene regulatory network: echinoderm skeletogenesis provides insights into evolution, plasticity and morphogenesis

Ettensohn

2009

Development

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Significant new insights have emerged from the analysis of a gene regulatory network (GRN) that underlies the development of the endoskeleton of the sea urchin embryo. Comparative studies have revealed ways in which this GRN has been modified (and conserved) during echinoderm evolution, and point to mechanisms associated with the evolution of a new cell lineage. The skeletogenic GRN has also recently been used to study the long-standing problem of developmental plasticity. Other recent findings have linked this transcriptional GRN to morphoregulatory proteins that control skeletal anatomy. These new studies highlight powerful new ways in which GRNs can be used to dissect development and the evolution of morphogenesis. IntroductionTo understand how development is encoded in the genome, biologists are turning increasingly to system-level approaches. The concept of transcriptional gene regulatory networks (GRNs) is proving to be a powerful one in this context. GRNs are ensembles of genes that encode transcription factors (TFs) and the genes that these proteins regulate. A central component of GRN analysis is the dissection of the cis-regulatory control systems of genes. Cisregulatory systems consist of non-coding DNA sequences that control when and where genes are transcribed. They are often viewed as modular, information-processing systems (Davidson, 2006). GRN analysis attempts to identify not only the functional interactions among genes, but also the relevant cis-regulatory DNA sequences, the proteins that bind to these sequences, and the logic by which cis-regulatory systems control gene transcription.The GRNs that operate during embryonic development (developmental GRNs) are highly dynamic. New interactions between genes are continually established as old interactions are modified or discarded. Inputs from cell signaling pathways, and intrinsic properties of regulatory networks themselves, contribute to the dynamic nature of GRNs (see Davidson, 2006). The genomic regulatory states of embryonic cells, which are a reflection of the concentrations and activities of hundreds of TFs and the global patterns of gene activity they evoke, are thus ever changing.This review considers recent studies that have applied the GRN concept in new and informative ways to examine developmental plasticity (that is, the ability of embryonic cells to switch developmental pathways), morphogenesis, and the evolution of developmental programs. It focuses on a GRN that controls skeletogenesis in sea urchins, a group of animals belonging to the phylum Echinodermata that has proven to be particularly useful for the analysis of GRNs in early development. GRNs that underlie cell specification are presently understood in greater detail in the sea urchin than in any other metazoan embryo, although work is ongoing in several other experimental models (Koide et al., 2005;Stathopoulos and Levine, 2005;Ge et al., 2006;Satou et al., 2008). For general reviews of GRNs in early sea urchin development, and of the methods used to construct and represe...

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Widespread cloning in echinoderm larvae

Cited by 74 publications

References 11 publications

Building divergent body plans with similar genetic pathways

Building divergent body plans with similar genetic pathways

Essential elements for translation: the germline factor Vasa functions broadly in somatic cells

Lessons from a gene regulatory network: echinoderm skeletogenesis provides insights into evolution, plasticity and morphogenesis

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