Stem cells in Nanomia bijuga (Siphonophora), a colonial animal with localized growth zones

Abstract

Background: Siphonophores (Hydrozoa) have unparalleled colony-level complexity, precision of colony organization, and functional specialization between zooids (i.e., the units that make up colonies). Previous work has shown that, unlike other colonial animals, most growth in siphonophores is restricted to one or two well-defined growth zones that are the sites of both elongation and zooid budding. It remained unknown, however, how this unique colony growth and development is realized at the cellular level.

Asymmetric Distribution of pl10 and bruno2, New Members of a Conserved Core of Early Germline Determinants in Cephalochordates

“…Accumulating evidence suggests that pl10 often plays a role in the germline in metazoans. In addition to Drosophila, pl10 orthologs are expressed in the germinal cells or their derivatives in the annelid Platynereis dumerilii (Rebscher et al, 2007;Gazave et al, 2013), the platyhelminth Dugesia japonicum (Shibata et al, 1999; reported as vasa-related genes) several hydrozoan cnidarian species (Leclère et al, 2012;Siebert et al, 2015), the ctenophore Mnemopsis leydii (Alié et al, 2011), the sponge Sycon ciliatum (Leininger et al, 2014), and in the colonial urochordate B. schlosseri (Rosner et al, 2009). vasa is coexpressed with pl10 in the latter, similarly to our results in B. lanceolatum.…”

The histology of Nanomia bijuga (Hydrozoa: Siphonophora)

“…Specimens were collected in Monterey Bay on Sep 29, 2012 via blue-water diving from a depth of 10-20 m. The specimens examined here were also used for the histological examinations of stem cells by Siebert et al (2015). Slides with representative thick sections and three additional whole N. bijuga specimens collected on the same dive have been deposited in the Museum of Comparative Zoology at Harvard, accession numbers IZ 50112-IZ 50016.…”

“…Siebert et al (2011) quantified differential gene expression between zooids using RNA-seq, and demonstrated the first in situ mRNA hybridizations in the species. Siebert et al (2015) described the distribution of stem cells throughout N. bijuga, finding that they are restricted to the growth zones, young zooids, and particular regions of some mature zooids.…”

PL10 DEAD‐Box Protein is Expressed during Germ Cell Differentiation in the Reptile Podarcis sicula (Family Lacertidae)

“…In recent years, a number of "germ line factors" driving germ cell differentiation in both sexes have been identified in Sharma and Jankowsky, 2014;Kozin and Kostyuchenko, 2015;Siebert et al, 2015;Fierro-Constaín et al, 2017). These genes encode for DEAD-box ATP-dependent RNA helicases (Linder et al,'89) and proteins found in all eukaryotes and most prokaryotes (e.g., Schmid and Linder, '92;Fujiwara et al, '94;Komiya et al, '94;Fabioux et al, 2004;Zhou et al, 2010).…”

“…DDX4/Vasa proteins are expressed in both male and female germ cells (Lasko and Ashburner,'88) and are essential in gametogenesis and germ cell specification during embryogenesis (Raz, 2000). Nonetheless, in some animals, DDX4/Vasa proteins are also expressed in stem cells of diverse origin, in which they contribute to cell cycle and developmental regulation (Leclère et al, 2012;Kozin and Kostyuchenko, 2015;Siebert et al, 2015;Yajima and Wessel, 2015;Fierro-Constaín et al, 2017). In other animals, their expression appears to be restricted to the germ cell lineage (Zhou et al, 2010).…”