Steroidogenic Acute Regulatory Protein in Eels: cDNA Cloning and Effects of ACTH and Seawater Transfer on Its mRNA Expression

Li, Yuanyou; Inoue, Koji; Takei, Yoshiyuki

doi:10.2108/zsj.20.211

Cited by 43 publications

(16 citation statements)

References 35 publications

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“…This finding is in agreement with previous data in several fish species where StAR is mainly expressed in the steroidogenic tissues (Bauer et al 2000, Li et al 2003, Goetz et al 2004, although it is in contraposition to the results obtained in other species, where StAR mRNA expression has been described in extragonadal and extra-adrenocortical tissues, such as the brain and heart of the freshwater stingray (Nunez et al 2005); the kidney of Atlantic croacker (Nunez & Evans 2007); the intestine, pyloric ceca, spleen, and kidney of trout (Kusakabe et al 2002); human fetal and adult kidney (Sugawara et al 1995); and several areas of the human brain (King et al 2002). Therefore, StAR tissue distribution can be slightly different according to the species, and its role in these other tissues remains to be clarified.…”

Section: Discussionsupporting

confidence: 94%

“…StAR cDNA has been previously cloned from rainbow trout, and several regions of the protein showed a high degree of homology with human StAR (Kusakabe et al 2002), especially in the C-terminal region, which contains hydrophobic sites for cholesterol binding (Tsujishita & Hurley 2000). Concerning fish studies, StAR transcripts have been detected in the steroidogenic tissues of rainbow trout, and the levels of StAR transcripts in the head kidney tissue, containing the steroidogenic interrenal cells, have been shown to increase in response to severe acute stress (Kusakabe et al 2002, Geslin & Auperin 2004 or when ACTH was injected in eels (Li et al 2003), suggesting that StAR is an important regulator of corticosteroidogenesis in fish. Despite these results for several fish species, there is relatively little information on StAR gene expression and regulation in perciform fish.…”

Section: Introductionmentioning

confidence: 99%

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Stress-induced regulation of steroidogenic acute regulatory protein expression in head kidney of Gilthead seabream (Sparus aurata)

Castillo¹,

Castellana²,

Acerete³

et al. 2007

Journal of Endocrinology

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Steroidogenic acute regulatory protein (StAR) transfers cholesterol over the inner mitochondrial membrane. In mammals, StAR controls this rate-limiting step of steroidogenesis, but its expression and regulation has not been well explored in fish. The present work investigates StAR mRNA expression in the head kidney of the gilthead seabream (Sparus aurata) under different stressors. We have cloned the StAR cDNA (1461 bp) in seabream (accession number EF640987), which has an open reading frame of 861 nucleotides encoding a polypeptide of 286 aa, and displays high sequence identity with StAR of other fish and mammalian counterparts. Seabream StAR transcripts were found to be expressed exclusively in head kidneys and gonads. In fish under acute stress (chased with a net), plasma cortisol levels peaked within 1 h, were still high after 6 h, and decreased after 16 h, although no increases in head kidney StAR expression were observed at any time post-stressor. Fish under chronic high-density stress showed cortisol levels 90-fold higher than controls and StAR mRNA levels increased threefold. Lipopolysaccharide (LPS) injection increased head kidney StAR mRNA levels after 6 h, reached a maximum at 12 h, and decreased until 72 h. When the head kidney cells were incubated in vitro and treated with ACTH or LPS, ACTH induced an increase in StAR expression as expected, but LPS induced a reduction in StAR expression. In conclusion, StAR expression in seabream head kidneys is highly regulated by different stressors.

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Section: Discussionsupporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Stress-induced regulation of steroidogenic acute regulatory protein expression in head kidney of Gilthead seabream (Sparus aurata)

Castillo¹,

Castellana²,

Acerete³

et al. 2007

Journal of Endocrinology

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“…The short P. motoro StAR transcript (1324 bp) isolated by 3 -RACE may result from the use of an atypical polyadenylation signal (CATAAA) starting at 1306 bp. StAR transcripts of multiple sizes are common in other vertebrates, including zebrafish (1500, 2500 and 4500 bp), rainbow trout (2300, 4300 and 9900 bp) and humans (1600, 4400 and 7500 bp) (Sugawara et al 1995b, von Hofsten et al 2002, Li et al 2003. The rapid induction of steroidogenesis by peptide hormones and other factors depends on the translation of StAR mRNA, but not on StAR gene transcription, which implies that a significant pool of Figure 6 The long form of the P. motoro StAR transcript contains a short interspersed repetitive element.…”

Section: Discussionmentioning

confidence: 99%

“…Characterization of the structure and regulation of StAR from fishes will greatly enhance our understanding of the role of steroidogenesis in maintaining homeostasis in these animals. The sequences of cDNA clones encoding teleost forms of StAR have recently been determined and studies of StAR regulation in gonadal and adrenocortical tissues of teleosts have been conducted (Bauer et al 2000, Kusakabe et al 2002b, von Hofsten et al 2002, Li et al 2003, Geslin & Auperin 2004. However, the nature of the teleost head kidney, a tissue composed of adrenocortical as well as several other cell types, complicates the study of steroidogenesis in these fishes.…”

Section: Introductionmentioning

confidence: 99%

Cloning and characterization of cDNAs encoding steroidogenic acute regulatory protein from freshwater stingrays (Potamotrygon spp.)

Nunez¹,

Piermarini²,

Evans³

et al. 2005

Journal of Molecular Endocrinology

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The steroidogenic acute regulatory protein (StAR) is critical to the regulated synthesis of steroids in vertebrates. We have isolated cDNA sequences encoding StAR in the freshwater stingrays Potamotrygon hystrix and P. motoro. A single P. hystrix StAR transcript (3376 bp) and two overlapping P. motoro StAR transcripts (1272 and 3365 bp) were isolated. The P. hystrix and P. motoro StAR transcripts contain open reading frames encoding proteins of 284 amino acids that are 99% identical to each other and 56-64% identical to other StAR proteins. Pregnenolone synthesis by green monkey kidney (COS-1) cells transfected with an expression construct encoding a human cholesterol side chain cleavage/adrenodoxin reductase/adrenodoxin fusion protein was increased 16-fold by coexpression with a pCMV5/P. motoro StAR expression construct. Northern blot analysis revealed a single 4000 bp StAR transcript in the P. motoro interrenal gland, but RT-PCR indicates StAR mRNA is also expressed in the brain, gonads, atria, ventricle, gill (female only) and muscle (female only). Expression in extragonadal and extraadrenocortical tissues is an indication that StAR may be critical to processes other than steroidogenesis. The longest P. motoro StAR transcript contains a sequence with great similarity to short interspersed repetitive elements found in other elasmobranchs. This study is the first to isolate and characterize elasmobranch StAR cDNA sequences and to demonstrate the activity of a nonmammalian StAR protein in a heterologous expression system.

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“…A series of studies were undertaken to specifically examine the possible sites of inhibitory action of cortisol on four different levels of steroidogenesis, as shown in Figure 1. These were the rate-limiting step in gonadal steroidogenesis is the cAMP-regulated transfer of cholesterol (by the activation of the cholesterol transporter, steroidogenic acute regulatory (StAR) protein) from the cytosol of steroidogenic cells into the inner chamber of the mitochondria, or the expression of the gene encoding for StAR protein [26][27][28][29][30] (A), the conversion of cholesterol to pregnenolone (P5) in the inner mitochondrial chamber by the action of the enzyme, cytochrome P450 side chain cleavage (P450scc) (B), the biotransformation of progestogens to androgenic steroids by enzymes associated with the smooth endoplasmic reticulum of the thecal cells (C), and the aromatization of the androgenic steroids to estrogens by specific isoforms of cytochrome P450 aromatase (P450arom) within the granulosal cells (D).…”

Section: Introductionmentioning

confidence: 99%

Cortisol Inhibition of 17b-Estradiol Secretion by Rainbow Trout Ovarian Follicles Involves Modulation of Star and P450scc Gene Expression

Barkataki¹,

Aluru²

2013

J Aquac Res Development

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Maternal stress associated with elevated maternal cortisol levels has well-demonstrated adverse affects on reproduction in vertebrates, including impaired ovarian steroidogenesis. Currently, the potential sites of action of cortisol on ovarian function are not known. Studies were carried out to examine the mechanism(s) by which cortisol suppresses steroidogenesis by mid-vitellogenic stage rainbow trout (Oncorhynchus mykiss) ovarian follicles. 17b-Estradiol and testosterone synthesis, and the expression of key steroidogenesis-related genes (using real time RT-PCR) were measured. Follicles were also incubated in the presence of several tritium-labelled steroids, and the tritium-labeled steroid products were separated by reverse-phase HPLC to look for possible affects of cortisol on specific steroidogenic enzyme function. Cortisol inhibited 17b-estradiol and testosterone synthesis, but had no affect on the formation of tritium-labelled estrogens from any of the tritium-labeled substrates, suggesting that the suppressive action of the glucocorticoid did not operate by inhibiting estrogen synthesis from androgens. Conversely, in the presence of cortisol in the medium, the relative expression of genes encoding for steroidogenic acute regulatory (StAR) protein and P450 side chain cleavage (P450scc) enzyme was suppressed, suggesting that the cortisol inhibition of steroidogenesis is prior to the synthesis of progestogens, possibly inhibiting either the expression and/or turnover of the genes encoding for StAR and P450scc proteins. The study shows that maternal stress during the critical phase of follicle vitellogenesis will have deleterious effects on oocyte development and growth.

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Steroidogenic Acute Regulatory Protein in Eels: cDNA Cloning and Effects of ACTH and Seawater Transfer on Its mRNA Expression

Cited by 43 publications

References 35 publications

Stress-induced regulation of steroidogenic acute regulatory protein expression in head kidney of Gilthead seabream (Sparus aurata)

Stress-induced regulation of steroidogenic acute regulatory protein expression in head kidney of Gilthead seabream (Sparus aurata)

Cloning and characterization of cDNAs encoding steroidogenic acute regulatory protein from freshwater stingrays (Potamotrygon spp.)

Cortisol Inhibition of 17b-Estradiol Secretion by Rainbow Trout Ovarian Follicles Involves Modulation of Star and P450scc Gene Expression

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