Receptor mediated mineralocorticoid action in alga cell mutants

Mirshahi, Massoud; Mirshahi, Ali; Nato, A.; Agarwal, M.K.

doi:10.1016/0014-5793(92)81479-6

Cited by 10 publications

(12 citation statements)

References 19 publications

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“…RPE cytosol, equili brated with 20 nM 3H-RU 26752, was incu bated with 10 pg rabbit anti-MCR (+) or control (-) IgG, and the quantity precipi tated in the presence of goat antirabbit IgGagarose was determined in triplicate. The results are expressed as cpm/mg protein ± SE [16][17][18][26][27][28], The change in the conformation of the steroid-receptor complex in the presence of heat and/or high salt is a uni versal feature of the DNA-binding domain of the steroid receptor superfamily [1][2][3], Data in figure 3 show a three fold increase in the amount of radioactivity that could be eluted from DNA cellulose when 3H-RU 26752-RPE cytosol was allowed to stand at 25 °C for 45 min above the control level at 4°C. The radioactivity increased from 222 cpm/mg protein at 4°C to 642 cpm/mg protein after 45 min at 25°C.…”

Section: Resultsmentioning

confidence: 99%

Immunochemical Demonstration of the Mineralocorticoid Receptor in Ocular Tissues

Mirshahi

Sedighian

et al. 1997

Neuroendocrinology

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We studied the presence of the mineralocorticoid receptor (MCR) in the eye with the aid of a number of immunochemical techniques. Immunoblotting with a polyclonal antibody, directed against the rat renal MCR, revealed a single band of about 102 kD in extracts prepared from whole bovine or rat retina similar to that observed in cytosol from the kidney and myocardium from these species. Isolated cells of the bovine retinal pigment epithelium (RPE) similarly exhibited a 98- to 102-kD band in Western blots developed with the aid of anti-MCR antiserum. The 98- to 102-kD band was also obtained following autoradiography of RPE cytosol irradiated in the presence of ³H-R 5020. This fluorographic pattern was abolished when RU 26752, an antagonist specific to the MCR, was allowed to compete with radiolabelled promegestone. The MCR-³H-RU 26752 complex in RPE cytosol underwent heat activation, as judged by binding to DNA cellusose, and could also be precipitated by anti-MCR IgG. In primary cultures, the proliferation of the RPE cells was inhibited by the two MCR-specific antagonists RU 26752 and ZK 91587. The loss of the MCR-specific immunofluorescence in RPE cells after only 3 passages in culture was associated with refractoriness to the inhibitory effect of both of these spironolactones. Immunohistochemistry, using MCR-specific antiserum, revealed strong fluorescence in specific areas of the rat eye. In the retina, immunopositivity was observed in Müller cells, external and internal limiting membranes, the vitreous base lining and in the pigment epithelium. Epithelial cells of the ciliary body, iris and cornea also exhibited strong MCR-specific immunofluorescence. Thus, both the epithelial and the nonepithelial compartments of the ocular tissues form interesting new targets to delineate the mechanism of action of mineralotropic hormones.

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Section: Resultsmentioning

confidence: 99%

Immunochemical Demonstration of the Mineralocorticoid Receptor in Ocular Tissues

Mirshahi

Sedighian

et al. 1997

Neuroendocrinology

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“…This procedure increases affinity of Chfamydomonas protein for DNA cellulose [22,23], in close similarity with the animal steroid receptors ( Fig. 1; [29]).…”

Section: Receptor-mediated Transactivation Of Genesmentioning

confidence: 95%

“…R-5020 can also be covalently linked to the carrier in alga by a photochemical procedure, further suggesting structural and functional kinship with the ligand binding domain in animal steroid receptors [22,23].…”

Section: Receptor-mediated Transactivation Of Genesmentioning

confidence: 99%

“…Cells surviving the inhibitory action of RU 26752 are afterwards refractory to this spirolactone, possibly due to an enzymatic adaptation, or a mutant receptor, or both [23]. This effect in a photosynthetic alga recalls growth inhibition by deoxycorticosterone in nonphotosynthetic fungi and bacteria [7,12], where Na/K balance is perturbed [24].…”

Section: Cellular Function Of Steroidsmentioning

confidence: 99%

“…A polyclonal antibody against the 107 kDa rat kidney mineralocorticoid receptor recognizes the 52 kDa alga carrier during immune precipitation and immune displacement assays [22,23].…”

Section: Receptor-mediated Transactivation Of Genesmentioning

confidence: 99%

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Receptors for mammalian steroid hormones in microbes and plants

Agarwal

1993

FEBS Letters

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Steroids are of universal occurrence, present variously as cell wall constituents and bioregulators. A number of bacteria, fungi, and photosynthetic vascular plants synthesize steroids that are honnonally active in the animal world. The cellular effect of such steroids in microbes and plants appears by and large to be comparable to that in mammals. Available evidence suggests that steroid action in botanical phyla is mediated via receptors organized in a manner similar to that seen in animals. Therefore, the ancestry of ligand induced transactivation via zinc finger proteins appears to date farther back than the early Cambrian burst of metazoan evolution 500 million years ago.Microbe; Plant; Steroid; Hormone; Receptor 1. STEROID DISTRIBUTION AND SYNTHESIS formed to steroids hormonally active in animals and plants [6-81. Receptor mediated control of transcription by steroid hormones (Fig. 1) is a subject of much contemporary interest in mammalian biology. In microbes and plants, the evidence for distribution, synthesis, and physiological action, of steroids has remained rather circumscribed, and sometimes even contradictory. This minireview traces the role played by steroids as messengers at various levels of evolution, as a prelude to understanding receptor origin for further experimental inquiry.Cholesterol is the common starting material in animals for P450 mediated synthesis of all classes of steroid hormones [9]. Plant species have been variously shown to contain glucocorticoids (cortisol), mineralocorticoids (deoxycorticosterone), progestins (progesterone), androgens (testosterone), estrogens (estradiol and estrone) and even the insect moulting hormone ecdysone [2,[5][6][7]10,, as shown in Table I.Life on earth is believed to have originated some 4 billion years ago from about 30 biologically useful precursors, formed from simple inorganic matter under the influence of the cosmic energy reaching our planet. Steroids are of universal occurrence, present in the cell variously as membrane constituents, chemical messengers, vitamins, cytotoxins, and hormones [1,2]. CELLULAR FUNCTION OF STEROIDSWhereas prokaryotic transformation of steroids is rich in diversity [3], the synthesis of sterols follows two major routes in higher organisms [4]. Squalene 2,3-oxide, formed from acetate via common pathways, is cyclized either to lanosterol in non-photosynthetic eukaryotes (fungi, animals), or to cycloartenol in photosynthetic phyla [4]. Insects transform steroids and ster01s ingested during feeding [2]. Plant sterols, saponins, cardiac glycosides, and alkaloids are of much biomedical value, but have no demonstrated counterparts or hormonal role in mammals [5]. Several bacterial and plant species synthesize cholesterol which is then transEarlier studies had shown that bacteria, mycoplasma (PPLO), and fungi respond to sterols and steroids in bewildering ways, ranging from vitamin-like to antimicrobial [7]. Mammalian gonadal hormones generally inhibit the growth of bacteria, in particular the Grampositive organisms [7,11]....

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1993

FEBS Letters

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Receptor mediated mineralocorticoid action in alga cell mutants

Cited by 10 publications

References 19 publications

Immunochemical Demonstration of the Mineralocorticoid Receptor in Ocular Tissues

Immunochemical Demonstration of the Mineralocorticoid Receptor in Ocular Tissues

Receptors for mammalian steroid hormones in microbes and plants

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