Sequence of Two mRNAs Encoding Active Rat Tryptophan Hydroxylase

Darmon, Michèle; Guibert, Bernard; Leviel, Vincent; Ehret, M.; Maître, Michel; Mallet, Jacques

doi:10.1111/j.1471-4159.1988.tb04871.x

Cited by 125 publications

(99 citation statements)

References 26 publications

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“…2 RT-PCR analysis of TPH transcripts in the retina of adult Brown Norway rats. The size of the amplified products is 254 bp (lane1) and, as demonstrated by sequencing, corresponds exactly to a fragment of mRNAs for TPH cloned by Darmon et al (1988). Lane 2, negative control, H20; M, marker standard.…”

Section: Discussionmentioning

confidence: 85%

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Serotonin synthesis and its light–dark variation in the rat retina

Chanut

Nguyen‐Legros²,

Labarthe

et al. 2002

Journal of Neurochemistry

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Retinal circadian rhythms are driven by an intrinsic oscillator, using chemical signals such as melatonin, secreted by photoreceptor cells. The purpose of the present work was to identify the origin of serotonin, the precursor of melatonin, in the retina of adult rat, where no immunoreactivity for serotonin or tryptophan hydroxylase had ever been detected. To demonstrate local synthesis of serotonin in the rat retina, substrates of tryptophan hydroxylase, the first limiting enzyme in the serotonin pathway, have been used. Tryptophan, in the presence of an inhibitor of aromatic amino acid decarboxylase, enhanced 5-hydroxytryptophan levels, whereas a-methyltryptophan, a competitive substrate inhibitor, was hydroxylated into a-methyl-5-hydroxytryptophan. Tryptophan hydroxylase substrate concentration was higher in the dark period than in the light period, and formation of hydroxylated compounds was increased. The presence of tryptophan hydroxylase mRNA in the rat retina was confirmed by RT-PCR. Taken together, the results support the local synthesis of serotonin by tryptophan hydroxylation, this metabolic pathway being required more critically when 5-HT is used for melatonin synthesis.

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Section: Discussionmentioning

confidence: 85%

“…described (Table 2) (Darmon et al 1988). Their specificity was analysed by comparing their sequences to various gene sequence databases, using the European Molecular Biology Laboratory (EMBL) Network File Server and the Fasta Program (Pearson and Lipman 1988).…”

Section: Rt-pcrmentioning

confidence: 99%

Serotonin synthesis and its light–dark variation in the rat retina

Chanut

Nguyen‐Legros²,

Labarthe

et al. 2002

Journal of Neurochemistry

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“…The TPH gene has been cloned from a variety of species including rodents, rabbits, and humans (Darmon et al, 1986(Darmon et al, , 1988Grenett et al, 1987;Boularand et al, 1990;Stoll et al, 1990;Kim et al, 1991;Tipper et al, 1994). In general, the rodent studies showed that cDNA probes hybridized to two mRNA species from RNA isolated from rat pineal or mouse mastocytoma cells (Dannon et al, 1988;Stoll et al, 1990;Kim& al., 1991).…”

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confidence: 99%

Regional Distribution and Cellular Expression of Tryptophan Hydroxylase Messenger RNA in Postmortem Human Brainstem and Pineal Gland

Austin

O’Donnell

1999

Journal of Neurochemistry

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Abstract:The characterization and cellular localization of tryptophan hydroxylase mRNA in the human brainstem and pineal gland were investigated by using northern blot analysis and in situ hybridization histochemistry. Northern analysis of human pineal gland revealed the presence of two mRNA species that were absent in RNA isolated from human raphe. In situ hybridization experiments revealed very dense hybridization signal corresponding to tryptophan hydroxylase mRNA in cells throughout the pineal gland. In contrast, tryptophan hydroxylase mRNA was heterogeneously distributed in neurons in the dorsal and median raphe nuclei. Within the dorsal raphe, the ventrolateral and interfascicular subnuclei contained the greatest number of tryptophan hydroxylase mRNA-positive neurons. Also, the cellular concentration of tryptophan hydroxylase mRNA varied widely within the dorsal and median raphe. Comparison of the cellular concentration of tryptophan hydroxylase mRNA between the pineal gland and the raphe nuclei revealed an 11 -and 46-fold greater average grain density of tryptophan hydroxylase mRNA positive cells in the pineal gland compared with the dorsal and median raphe, respectively. These findings are the first to demonstrate the cellular localization of tryptophan hydroxylase mRNA in the human brain and pineal gland as well as heterogeneity in the cellular concentration within and between these tissues.

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“…Physicochemical, enzymic and immunochemical properties differed between TPHs of neural and non-neural tissue origin, and it is accepted that neural TPH might be a different entity from the non-neural enzyme [8,10,12,13]. Complimentary DNAs of TPH have been cloned from various sources but no differences or only trivial variation in amino acid sequences were found among them [14][15][16][17][18][19]. The molecular basis of differences between the neural and non-neural enzymes has not yet been explained.…”

mentioning

confidence: 99%

Proteasome‐driven turnover of tryptophan hydroxylase is triggered by phosphorylation in RBL2H3 cells, a serotonin producing mast cell line

Iida

Sawabe

Kojima

et al. 2002

European Journal of Biochemistry

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We previously demonstrated in mast cell lines RBL2H3 and FMA3 that tryptophan hydroxylase (TPH) undergoes very fast turnover driven by 26S-proteasomes [Kojima, M., Oguro, K., Sawabe, K., Iida, Y., Ikeda, R., Yamashita, A., Nakanishi, N. & Hasegawa, H. (2000) J. Biochem (Tokyo) 2000, 127,[121][122][123][124][125][126][127]. In the present study, we have examined an involvement of TPH phosphorylation in the rapid turnover, using non-neural TPH. The proteasome-driven degradation of TPH in living cells was accelerated by okadaic acid, a protein phosphatase inhibitor. Incorporation of 32 P into a 53-kDa protein, which was judged to be TPH based on autoradiography and Western blot analysis using anti-TPH serum and purified TPH as the size marker, was observed in FMA3 cells only in the presence of both okadaic acid and MG132, inhibitors of protein phosphatase and proteasome, respectively. In a cell-free proteasome system constituted mainly of RBL2H3 cell extracts, degradation of exogenous TPH isolated from mastocytoma P-815 cells was inhibited by protein kinase inhibitors KN-62 and K252a but not by H89. Consistent with the inhibitor specificity, the same TPH was phosphorylated by exogenous Ca 2+ /calmodulindependent protein kinase II in the presence of Ca 2+ and calmodulin but not by protein kinase A (catalytic subunit). TPH protein thus phosphorylated by Ca 2+ /calmodulindependent protein kinase II was digested more rapidly in the cell-free proteasome system than was the nonphosphorylated enzyme. These results indicated that the phosphorylation of TPH was a prerequisite for proteasome-driven TPH degradation.Keywords: tetrahydrobiopterin; CaM kinase II; proteasome target; ubiquitin ligase; enzyme turnover.Tryptophan hydroxylase (TPH, EC 1.14.16.4), a member of a family of pterin-dependent aromatic amino acid hydroxylases [1], catalyzes the conversion of L-tryptophan to 5-hydroxy-L-tryptophan. This reaction is the initial and rate-limiting step in the biosynthesis of serotonin [2][3][4][5]. TPH has been extensively purified from various sources such as bovine pineal gland [6], mouse mastocytoma [7,8], and mammalian brains [9][10][11]. Physicochemical, enzymic and immunochemical properties differed between TPHs of neural and non-neural tissue origin, and it is accepted that neural TPH might be a different entity from the non-neural enzyme [8,10,12,13]. Complimentary DNAs of TPH have been cloned from various sources but no differences or only trivial variation in amino acid sequences were found among them [14][15][16][17][18][19]. The molecular basis of differences between the neural and non-neural enzymes has not yet been explained.Both types of cytosolic environment should be studied further to detect differences in the control of gene expression, post-translational modification, and turnover of the enzyme protein in a tissue-specific way.We have demonstrated with RBL2H3, an established cell line that expresses TPH in culture while retaining many of the characteristics of mast cells, that: (a) cellular TPH activity was ...

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Sequence of Two mRNAs Encoding Active Rat Tryptophan Hydroxylase

Cited by 125 publications

References 26 publications

Serotonin synthesis and its light–dark variation in the rat retina

Serotonin synthesis and its light–dark variation in the rat retina

Regional Distribution and Cellular Expression of Tryptophan Hydroxylase Messenger RNA in Postmortem Human Brainstem and Pineal Gland

Proteasome‐driven turnover of tryptophan hydroxylase is triggered by phosphorylation in RBL2H3 cells, a serotonin producing mast cell line

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