Linked Life Data

19754709

Source:http://linkedlifedata.com/resource/pubmed/id/19754709

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2009-9-16
pubmed:abstractText
In bilaterian animals, germ cells are specified by the inductive/regulative mode or the predetermined (germ plasm) mode. Among tetrapods, mammals and urodeles use the inductive mode, whereas birds and anurans use the predetermined mode. From histological data it has been predicted that some reptiles including turtles use the inductive mode. Examining turtle oocytes, we find that Dazl RNA, Vasa RNA, and Vasa protein are not localized, suggesting that germ plasm is not present. In turtle embryos at somite stages, primordial germ cells (PGCs) expressing Dazl lie on a path from the lateral posterior extraembryonic endoderm through the gut to the gonad as previously described. In gastrulating embryos, cells expressing Dazl are found in the blastoporal plate and subsequently below the blastoporal plate, indicating that PGCs are generated at the equivalent of the early posterior primitive streak of mammals. Vasa RNA is expressed in somatic cells of gastrula to early somite stages, and Vasa RNA and protein are expressed in PGCs of later embryos. Taken together the evidence strongly suggests that turtles, and other reptiles (lacertoid lizards) with the same location of PGCs in embryos, use the inductive mode of germ cell specification. Phylogenetic analysis of the available evidence supports the following hypotheses: (1) the inductive mode is basal among reptiles, indicating that this mode was maintained as basal tetrapods evolved to amniotes, (2) the predetermined mode arose twice within reptiles, and (3) the induced mode may be used in several lepidosaurs whose PGCs are located in an unusual pattern distributed around the embryo.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
1525-142X
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
11
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
525-34
pubmed:meshHeading
pubmed:articleTitle
Expression of Dazl and Vasa in turtle embryos and ovaries: evidence for inductive specification of germ cells.
pubmed:affiliation
Department of Cell and Developmental Biology, Weill Medical College of Cornell University, New York, NY 10065, USA. bachva@med.cornell.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't