Gene expression in the axolotl germ line: Axdazl, Axvh, Axoct‐4, and Axkit

A Comprehensive Expressed Sequence Tag Linkage Map for Tiger Salamander and Mexican Axolotl: Enabling Gene Mapping and Comparative Genomics in Ambystoma

“…The complex as a whole is an important, naturalistic model system because taxa are characterized by extensive interspecific and intraspecific variation for a number of ecologically important traits, including expression of metamorphic vs. nonmetamorphic (paedomorphic) life histories (Gould 1977;Shaffer and Voss 1996), timing of metamorphosis (Rose and Armentrout 1976;Voss and Smith 2005), cannibal vs. normal larval morphologies (Powers 1907;Hoffman and Pfennig 1999), infectious disease (Collins et al 2004), variation in adult coloration and pigment patterning (Reese 1969;Parichy 1996Parichy , 1998, and variation in general morphology (Shaffer 1984;Irschick and Shaffer 1997). In addition, these salamanders are important laboratory models for olfaction (Marchand et al 2004;Park et al 2004), vision (Thoreson et al 2004;Chichilnisky and Reike 2005), cardiogenesis (Denz et al 2004;Zhang et al 2004), embryogenesis (Bachvarova et al 2004;Ericsson et al 2004), and postembryonic development (Parichy 1998;Voss and Smith 2005), including organ and tissue regeneration (Christensen et al 2002;Schnapp and Tanaka 2005). Both natural and laboratory-based research areas are in need of a comprehensive genome map that can be used to identify the position and effect of loci that contribute to phenotypic variation and that can be used to compare features of the salamander genome to other vertebrates.…”

Identification of a pou2 ortholog in Chinese sturgeon, Acipenser sinensis and its expression patterns in tissues, immature individuals and during embryogenesis

“…Aspou2 mRNA was widespread in diverse tissues, with abundant transcripts in the pituitary, muscle and almost all subdivisions of the brain, lower expressions in the kidney, heart, ovary, spleen, intestine and fat, and unable to detect in the liver. To date, there is no species with the same expression pattern of Aspou2, including zebrafish (Takeda et al 1994), medaka (Sanchez-Sanchez et al 2010, cod (Holen et al 2010), frog (Hinkley et al 1992), axolotl (Bachvarova et al 2004), tammar (Frankenberg et al 2010), chicken (Lavial et al 2007), mouse (Pesce et al 1998;Palmieri et al 1994), cat (Yu et al 2009), rabbit (Shi et al 2008), bovine (van Eijk et al 1999) and human (Takeda et al 1992). Comparing the expression of the class V POU family genes in the liver, we found that among these species, only tammar Pou5f1 mRNAs were detected in the liver, except for medaka and mouse in which no one has detected the liver expression characteristics of class V POU family genes so far, suggesting that during the evolution, tammar Pou5f1 gene might get some additional function in the liver.…”

“…These factors played important roles in the control of the activities of VegT, bcatenin, and nodal and BMP4 signaling pathways and inhibited premature and incorrect differentiation of embryonic cells (Cao et al 2006(Cao et al , 2007Snir et al 2006). In axolotl, only a single class V POU gene, AxOct4, was identified, which was expressed in the epiblast, in the posterior mesoderm of late gastrulae, and in diplotente growing oocytes (Bachvarova et al 2004). In chicken, the class V POU gene, cPouV, was required for the maintenance of pluripotency and self-renewal of ESC (Lavial et al 2007).…”

Pluripotency and lineages in the mammalian blastocyst: An evolutionary view

“…[17][18][19][20][21] For example, the Oct4 and Nanog homologs in chick can at least partially sustain mouse ES cell function in culture. 22 While these reports indicate functional conservation of these factors among vertebrates, some territories of early expression are not conserved in nonmammals 23 and the wiring of the network in non mammals is not known.…”

“…Several labs had previously identified the Pou5 class of Oct4-related genes in various non-mammalian vertebrates, claiming that these genes were the true homologs of mammalian Oct4 based on sequence similarity, early embryonic expression, syntenic conservation or functional equivalence in ES assays. 17,18,21,22 However, recent reports claim that in the early vertebrate lineage the Pou5 class was represented by a single gene, which was duplicated before the mammalian radiation to give rise to the two Pou5 genes found today in noneutherian mammals. 35,36 One copy was subsequently lost in eutherian mammals, resulting in the single Oct4 gene present in mouse and humans.…”