Synthesis of Melatonin by the Pineal Modified Photoreceptors of Birds Immunocytochemical Localization of Hydroxyindole‐o‐methyltransferase

Guerlotté, Jérôme; Voisin, Pierre; Brisson, Paul; Faure, Jean‐Pierre; Collin, Jean‐Pierre

doi:10.1016/0248-4900(88)90098-6

Cited by 16 publications

(5 citation statements)

References 12 publications

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“…They were then incubated simultaneously (overnight, 4°C) with a mouse monoclonal anti-digoxigenin antibody (Roche Applied Science; 1/200 dilution) and with purified anti-HIOMT immunoglobulins (rabbit IgG 20 ng/ml; Guerlotté et al 1988) in PBStween-BSA. As a negative control, sections were incubated with 40 ng/ml of rabbit anti-LexA IgG (Affinity Bioreagents, Ozyme, Saint Quentin Yvelines, France).…”

Section: Combined Ish and Immunohistofluorescencementioning

confidence: 99%

Visual photoreceptor subtypes in the chicken retina: melatonin-synthesizing activity and in vitro differentiation

et al. 2012

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The chicken retina contains five visual photoreceptor subtypes, based on the specific opsin gene they express. In addition to the central role they play in vision, some or all of these photoreceptors translate photoperiodic information into a day-night rhythm of melatonin production. This indolic hormone plays an important role in the photoperiodic regulation of retinal physiology. Previous studies have stopped short of establishing whether melatonin synthesis takes place in all the photoreceptor spectral subtypes. Another issue that has been left unsettled by previous studies is when during development are retinal precursor cells committed to a specific photoreceptor subtype and to a melatoninergic phenotype? To address the first question, in situ hybridization of the five opsins was combined with immunofluorescent detection of the melatonin-synthesizing enzyme hydroxyindole O-methyltransferase (HIOMT, EC.2.1.1.4). Confocal microscopy clearly indicated that all photoreceptor spectral subtypes are involved in melatonin synthesis. To tackle the second question, retinal precursor cells were dissociated between embryonic day 6 (E6) and E13 and cultured in serum-free medium for 4 days to examine their ability to autonomously activate the expression of opsins and HIOMT. Real-time PCR on cultured precursors indicated that red-, green- and violet-sensitive cones are committed at E6, rods at E10 and blue-sensitive cones at E12. HIOMT gene expression was programmed at E6, probably reflecting the differentiation of early cones. The present study provides a better characterization of photoreceptor subtypes in the chicken retina and describes a combination of serum-free culture and real-time PCR that should facilitate further developmental studies.

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Section: Combined Ish and Immunohistofluorescencementioning

confidence: 99%

Visual photoreceptor subtypes in the chicken retina: melatonin-synthesizing activity and in vitro differentiation

et al. 2012

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“…Affinity-purified immunoglobulins against chicken HIOMT were obtained as previously described (GuerlottC et al, 1988). After 48 h of culture, pineal cells were rinsed with phosphatebuffered saline (PBS; pH 7.4) and fixed in 4% paraformaldehyde.…”

Section: Imrnunocytochemistrymentioning

confidence: 99%

N‐Acetylation of Serotonin Is Correlated with α₂‐ but Not with β‐Adrenergic Regulation of Cyclic AMP Levels in Cultured Chick Pineal Cells

Voisin

Camp

Collin

1990

Journal of Neurochemistry

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We investigated the role of cyclic AMP (cAMP) in alpha 2- and possible beta-adrenergic regulation of arylalkylamine-N-acetyltransferase (NAT), the penultimate enzyme in the biosynthesis of melatonin. The study was performed on primary cultures of dispersed chick pineal cells. Electron microscopy indicated that approximately 70% of the dispersed cells were modified photoreceptors. A similar proportion of melatoninergic cells was detected by immunocytochemical labeling of hydroxyindole-O-methyltransferase, the final enzyme in the biosynthesis of melatonin. Adrenergic agonists caused a sustained 50% inhibition of forskolin-augmented cAMP levels and NAT activity, with an alpha 2-adrenergic potency order of UK 14,304 greater than or equal to clonidine greater than norepinephrine greater than phenylephrine. Noradrenergic inhibition of 3-isobutyl-1-methylxanthine-augmented cAMP levels and NAT activity was reversed by yohimbine (an alpha 2-adrenergic antagonist) but not by prazosin (an alpha 1-adrenergic antagonist). The alpha-adrenergic inhibition of cAMP accumulation and NAT activity was prevented by pertussis toxin. Addition of propranolol (a beta-adrenergic antagonist) was necessary to observe an inhibitory effect of norepinephrine on cAMP levels but not on NAT activity. Similarly, the beta-adrenergic agonist isoproterenol transiently increased cAMP levels but did not affect NAT activity. The data indicate that the alpha 2-adrenergic inhibition of NAT activity in chick pineal cells is strongly correlated with an inhibition of cAMP accumulation. The lack of beta-adrenergic effect on NAT suggests that beta-adrenoceptors might be on a subset of cells that do not produce melatonin or that the beta-adrenergic-induced increase in cAMP levels is too transient to affect NAT.

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“…The antibodies directed against chicken HIOMT have been characterized in previous studies (Voisin et al, 1988;Guerlotte et al, 1988). Briefly, an antiserum was obtained in a rabbit immunized with a 30 00-pure preparation of HIOMT.…”

Section: Materials and Methods Antibodiesmentioning

confidence: 99%

“…To ensure that the immunostaining of the fusion protein on Western blots was not due to multiple reactivities of the antiserum, the experiment was performed with affinity-purified anti-HIOMT immunoglobulins. These were obtained by incubating the antiserum with the HIOMT protein band separated on a Western blot, followed by desorption of the immunoglobulins with a pH shock (Guerlotte et al, 1988). Goat serum anti-rabbit y-immunoglobulins (GAR; Sigma R-5506) and peroxidase-rabbit Abbreviations used: HIOMT, hydroxyindole 0-methyltransferase; poly(A)+ RNA, polyadenylated RNA. t To whom correspondence should be addressed.…”

Section: Materials and Methods Antibodiesmentioning

confidence: 99%

Molecular cloning and nucleotide sequence of a cDNA encoding hydroxyindole O-methyltransferase from chicken pineal gland

Voisin

Guerlotté

Bernard

et al. 1992

Biochemical Journal

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Hydroxyindole O-methyltransferase (EC 2.1.1.4) is the enzyme that catalyses the synthesis of melatonin in the pineal gland and in the retina. Polyadenylated RNA from chicken pineal glands was used to prepare a cDNA library in lambda gt11. The library was screened with an antiserum directed against chicken hydroxyindole O-methyltransferase, and one cDNA clone was isolated. The fusion protein expressed by phage lysogens was identified on Western blots as a 165 kDA immunoreactive protein (beta-galactosidase, 110 kDa; hydroxyindole O-methyltransferase, 38 kDa). The fusion protein exhibited hydroxyindole O-methyltransferase activity. Its Km values for N-acetyl-5-hydroxytryptamine and S-adenosylmethionine were 5 times those of the natural enzyme. The intrinsic activity of the fusion protein was approx. 0.25% that of the natural enzyme. The cDNA consisted of 1436 nucleotides, including a 1038-nucleotide sequence encoding a full-length 346-amino-acid hydroxyindole O-methyltransferase. Comparison with bovine hydroxyindole O-methyltransferase [Ishida, Obinata & Deguchi (1987) J. Biol. Chem. 262, 2895-2899] revealed 52% identity in nucleotide sequences and 44% identity in peptide sequences. Northern-blot analysis revealed the presence of hydroxyindole O-methyltransferase mRNA transcripts in chicken pineal gland and retina, but not in the telencephalon.

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Synthesis of Melatonin by the Pineal Modified Photoreceptors of Birds Immunocytochemical Localization of Hydroxyindole‐o‐methyltransferase

Cited by 16 publications

References 12 publications

Visual photoreceptor subtypes in the chicken retina: melatonin-synthesizing activity and in vitro differentiation

Visual photoreceptor subtypes in the chicken retina: melatonin-synthesizing activity and in vitro differentiation

N‐Acetylation of Serotonin Is Correlated with α₂‐ but Not with β‐Adrenergic Regulation of Cyclic AMP Levels in Cultured Chick Pineal Cells

Molecular cloning and nucleotide sequence of a cDNA encoding hydroxyindole O-methyltransferase from chicken pineal gland

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Synthesis of Melatonin by the Pineal Modified Photoreceptors of Birds Immunocytochemical Localization of Hydroxyindole‐o‐methyltransferase

Cited by 16 publications

References 12 publications

Visual photoreceptor subtypes in the chicken retina: melatonin-synthesizing activity and in vitro differentiation

Visual photoreceptor subtypes in the chicken retina: melatonin-synthesizing activity and in vitro differentiation

N‐Acetylation of Serotonin Is Correlated with α2‐ but Not with β‐Adrenergic Regulation of Cyclic AMP Levels in Cultured Chick Pineal Cells

Molecular cloning and nucleotide sequence of a cDNA encoding hydroxyindole O-methyltransferase from chicken pineal gland

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N‐Acetylation of Serotonin Is Correlated with α₂‐ but Not with β‐Adrenergic Regulation of Cyclic AMP Levels in Cultured Chick Pineal Cells