Expression and Alternative Processing of a Chicken Gene Encoding Both Growth Hormone-Releasing Hormone and Pituitary Adenylate Cyclase-Activating Polypeptide

McRory, John E.; Parker, Robin; Sherwood, Nancy M.

doi:10.1089/dna.1997.16.95

Cited by 94 publications

(19 citation statements)

References 49 publications

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“…These data strongly suggest that PACAP, instead of GHRH itself, may play the role of growth hormone-releasing factor in teleosts [12, 13]. Interestingly, PACAP and GHRH have been shown to be encoded by the same gene in non-mammalian species including teleosts [11, 59, 60]and birds [61], while they are encoded by two distinct genes in mammals. The difference in expression and localization between PACAP and GHRH in teleosts may be due to differential splicing and/or processing of the precursor [11, 59].…”

Section: Discussionmentioning

confidence: 99%

Pituitary Growth Hormone Secretion in the Turbot, a Phylogenetically Recent Teleost, Is Regulated by a Species-Specific Pattern of Neuropeptides

et al. 2001

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In mammals, growth hormone (GH) is under a dual hypothalamic control exerted by growth hormone-releasing hormone (GHRH) and somatostatin (SRIH). We investigated GH release in a pleuronectiform teleost, the turbot (Psetta maxima), using a serum-free primary culture of dispersed pituitary cells. Cells released GH for up to 12 days in culture, indicating that turbot somatotropes do not require releasing hormone for their regulation. SRIH dose-dependently inhibited GH release up to a maximal inhibitory effect of 95%. None of the potential stimulators tested induced any change in basal GH release. Also, neither forskolin, an activator of adenylate cyclase, nor phorbol ester (TPA), an activator of protein kinase C, were able to modify GH release, suggesting that spontaneous basal release already represents the maximal secretory capacity of turbot somatotropes. In contrast, forskolin and TPA were able to increase GH release in the presence of SRIH. In this condition (coincubation with SRIH), pituitary adenylate cyclase-activating polypeptide (PACAP) stimulated GH release, whereas none of the other neuropeptides tested (GHRHs; sea bream or salmon or chicken II GnRHs; TRH; CRH) had any significant effect. These data indicate that inhibitory control by SRIH may be the basic control of GH production in teleosts and lower vertebrates, while PACAP may represent the ancestral growth hormone-releasing factor in teleosts, a role taken over in higher vertebrates by GHRH.

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Section: Discussionmentioning

confidence: 99%

Pituitary Growth Hormone Secretion in the Turbot, a Phylogenetically Recent Teleost, Is Regulated by a Species-Specific Pattern of Neuropeptides

et al. 2001

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“…These findings are different from mammals, in which PACAP and GHRH are encoded in separate genes. Interestingly enough, ‘colocalization’ of PACAP and GHRH in the same gene has also been reported in amphibians [9]and birds [10]. These observations have led to the hypothesis that PACAP and GHRH are derived from the same ancestral gene and the splitting into two separate genes might have been a recent event occurred before the evolution of mammals [4].…”

Section: Introductionmentioning

confidence: 91%

Regulation of Growth Hormone Release in Common Carp Pituitary Cells by Pituitary Adenylate Cyclase-Activating Polypeptide: Signal Transduction Involves cAMP- and Calcium-Dependent Mechanisms

et al. 2002

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Pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the glucagon/secretin peptide family and its molecular structure is highly conserved among vertebrates. In this study, the role of PACAP in regulating growth hormone (GH) secretion in fish was examined in vitro using common carp pituitary cells under column perifusion. A dose-dependent increase in GH release was observed after exposing pituitary cells to increasing doses of ovine PACAP38 (oPACAP38) and PACAP27 (oPACAP27), but not vasoactive intestinal polypeptide (VIP). A lack of GH response to VIP stimulation is consistent with the pharmacological properties of PAC-1 receptors, suggesting that this receptor subtype may be involved in PACAP-induced GH secretion in carp species. Although the maximal GH responses induced by oPACAP38 and oPACAP27 were similar, the minimal effective dose and ED50 value for oPACAP38 were significantly lower than that for oPACAP27. These results may indicate that common carp PAC-1 receptors are more sensitive to stimulation by oPACAP38 than by oPACAP27. In parallel studies, oPACAP38 and oPACAP27 were also effective in increasing cAMP release, cellular cAMP content, total cAMP production, and intracellular Ca²⁺ ([Ca²⁺]_i) levels in common carp pituitary cells. Besides, the rise in [Ca²⁺]_i induced by oPACAP38 was blocked by removing extracellular Ca²⁺ ([Ca²⁺]_e) or by treatment with nifedipine, an inhibitor of voltage-sensitive Ca²⁺ channels (VSCC). The dose dependence of PACAP-stimulated GH release in common carp pituitary cells was mimicked by activating adenylate cyclase using forskolin, inhibiting cAMP degradation using IBMX, increasing functional levels of intracellular cAMP using CPT-cAMP, or inducing [Ca²⁺]_e entry using the Ca²⁺ ionophore A23187. In contrast, the GH-releasing effect of oPACAP38 was suppressed by treatment with the adenylate cyclase inhibitor MDL12330A, protein kinase A inhibitor H89, and VSCC blocker nifedipine, or by perifusion with a Ca²⁺-free culture medium. These results, as a whole, suggest that PACAP functions as a GH-releasing factor in common carp by activating pituitary receptors resembling mammalian PAC-1 receptors. Apparently, the GH-releasing action of PACAP is mediated through the adenylate cyclase/cAMP/protein kinase A pathway and [Ca²⁺]_e influx through VSCC.

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“…short (Ͻ20 codons) inserts in mature transcripts by "exon sliding" have been described in the Drosophila Ultrabithorax gene (62), porcine urokinase-like plasminogen activator (63), human ␤-adducin gene (64), chicken growth hormone-releasing hormone gene (65), and human presenilin-1 gene (66).…”

Section: Figmentioning

confidence: 99%

Molecular Enzymology of Mammalian Δ1-Pyrroline-5-carboxylate Synthase

Lin

Obie

et al. 1999

Journal of Biological Chemistry

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⌬1 -Pyrroline-5-carboxylate synthase (P5CS; EC not assigned), a mitochondrial inner membrane, ATP-and NADPH-dependent, bifunctional enzyme, catalyzes the reduction of glutamate to ⌬ 1 -pyrroline-5-carboxylate, a critical step in the de novo biosynthesis of proline and ornithine. We utilized published plant P5CS sequence to search the expressed sequence tag data base and cloned two full-length human P5CS cDNAs differing in length by 6 base pairs (bp) in the open reading frame. The short cDNA has a 2379-bp open reading frame encoding a protein of 793 residues; the long cDNA, generated by "exon sliding," a form of alternative splicing, contains an additional 6-bp insert following bp ؉711 of the short form resulting in inclusion of two additional amino acids in the region predicted to be the ␥-glutamyl kinase active site of P5CS. The long form predominates in all tissues examined except gut. We also isolated the corresponding long and short murine P5CS transcripts. To confirm the identity of the putative P5CS cDNAs, we expressed both human forms in ␥-glutamyl kinase-and ␥-glutamyl phosphate reductase-deficient strains of Saccharomyces cerevisiae and showed that they conferred the proline prototrophy. Additionally, we found expression of the murine putative P5CS cDNAs conferred proline prototrophy to P5CS-deficient Chinese hamster ovary cells (CHO-K1). We utilized stable CHO-K1 cell transformants to compare the biochemical characteristics of the long and short murine P5CS isoforms. We found that both confer P5CS activity and that the short isoform is inhibited by L-ornithine with a K i of ϳ0.25 mM. Surprisingly, the long isoform is insensitive to ornithine inhibition. Thus, the two amino acid insert in the long isoform abolishes feedback inhibition of P5CS activity by L-ornithine.

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Expression and Alternative Processing of a Chicken Gene Encoding Both Growth Hormone-Releasing Hormone and Pituitary Adenylate Cyclase-Activating Polypeptide

Cited by 94 publications

References 49 publications

Pituitary Growth Hormone Secretion in the Turbot, a Phylogenetically Recent Teleost, Is Regulated by a Species-Specific Pattern of Neuropeptides

Pituitary Growth Hormone Secretion in the Turbot, a Phylogenetically Recent Teleost, Is Regulated by a Species-Specific Pattern of Neuropeptides

Regulation of Growth Hormone Release in Common Carp Pituitary Cells by Pituitary Adenylate Cyclase-Activating Polypeptide: Signal Transduction Involves cAMP- and Calcium-Dependent Mechanisms

Molecular Enzymology of Mammalian Δ1-Pyrroline-5-carboxylate Synthase

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