Distribution of growth hormone—like immunoreactive cells and somatostatin receptors in the nervous system and Hatschek's pit of amphioxus, branchiostoma belcheri *

Fang, Yue; Weng, Youzhu

doi:10.1080/10020070612330005

Cited by 4 publications

(2 citation statements)

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“…Although Cyp19 and Hsd3β activities have been detected in amphioxus gonadal tissues (Callard et al 1984; Mizuta et al 2008), and although docking studies predict, for example, that Cyp19 can bind androgens (Callard et al 2011), the biochemical activity of most of these amphioxus enzymes still requires experimental confirmation. Nevertheless, based on this collection of amphioxus enzymes and supported by the presence of sex steroids in amphioxus (Chang et al 1985; Fang et al 2001; Takeda et al 2003; Mizuta and Kubokawa 2007), we hypothesize that a vertebrate-like sex steroid metabolism exists in cephalochordates. In contrast, amphioxus probably lacks Cyp21, which in vertebrates is an enzyme instrumental for corticosteroid synthesis.…”

Section: Discussionmentioning

confidence: 67%

“…In amphioxus, sex steroids, including progesterone, estrone, estradiol and testosterone, have been detected by RIA and immunohistochemical methods (Chang et al 1985; Fang et al 2001; Takeda et al 2003; Mizuta and Kubokawa 2007), and two steroid receptors, ER and SR, have been characterized (Bridgham et al 2008; Paris et al 2008; Katsu et al 2010; Callard et al 2011). Amphioxus ER is orthologous to vertebrate estrogen receptor (ER) and amphioxus SR is orthologous to the vertebrate steroid receptors (SR), including androgen receptor (AR), glucocorticoid receptor (GR), mineralocorticoid receptor, (MR) and progesterone receptor (PR) (Bridgham et al 2008; Paris et al 2008; Schubert et al 2008; Katsu et al 2010; Callard et al 2011).…”

Section: Discussionmentioning

confidence: 99%

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Evolution of Retinoid and Steroid Signaling: Vertebrate Diversification from an Amphioxus Perspective

Albalat

Brunet

Laudet

et al. 2011

Genome Biology and Evolution

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Although the physiological relevance of retinoids and steroids in vertebrates is very well established, the origin and evolution of the genetic machineries implicated in their metabolic pathways is still very poorly understood. We investigated the evolution of these genetic networks by conducting an exhaustive survey of components of the retinoid and steroid pathways in the genome of the invertebrate chordate amphioxus (Branchiostoma floridae). Due to its phylogenetic position at the base of chordates, amphioxus is a very useful model to identify and study chordate versus vertebrate innovations, both on a morphological and a genomic level. We have characterized more than 220 amphioxus genes evolutionarily related to vertebrate components of the retinoid and steroid pathways and found that, globally, amphioxus has orthologs of most of the vertebrate components of these two pathways, with some very important exceptions. For example, we failed to identify a vertebrate-like machinery for retinoid storage, transport, and delivery in amphioxus and were also unable to characterize components of the adrenal steroid pathway in this invertebrate chordate. The absence of these genes from the amphioxus genome suggests that both an elaboration and a refinement of the retinoid and steroid pathways took place at the base of the vertebrate lineage. In stark contrast, we also identified massive amplifications in some amphioxus gene families, most extensively in the short-chain dehydrogenase/reductase superfamily, which, based on phylogenetic and genomic linkage analyses, were likely the result of duplications specific to the amphioxus lineage. In sum, this detailed characterization of genes implicated in retinoid and steroid signaling in amphioxus allows us not only to reconstruct an outline of these pathways in the ancestral chordate but also to discuss functional innovations in retinoid homeostasis and steroid-dependent regulation in both cephalochordate and vertebrate evolution.

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