Analysis of the Post-translational Processing of α-MSH in the Pituitaries of the Chondrostean Fishes, Acipenser transmontanus and Polyodon spathula

Keller, H; Jm, Redding; Moberg, Gary P.; Rm, Dores

doi:10.1006/gcen.1994.1071

Cited by 12 publications

(3 citation statements)

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“…Does this precursor generate the g-MSH as an end-product? The concentration of POMC-related products in the intermediate pituitary of adult white sturgeon is approximately 513 pmol/pituitary (Keller et al, 1994). Hence, it should be possible to use mass spectrometry to quickly determine whether the sturgeon pituitary yields g-MSH as an endproduct.…”

Section: Post-translational Processing Mechanismsmentioning

confidence: 99%

Analyzing the evolution of the opioid/orphanin gene family

Dores

Lecaude

Bauer

et al. 2002

Mass Spectrometry Reviews

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Advances in molecular biology have made it possible to rapidly obtain the amino acid sequence of neuropeptide precursors-either by cloning and sequencing the cDNA that encodes the precursor, or by reconstructing the arrangement of exons and introns in a neuropeptide-coding gene through genomic approaches. The databases generated from these molecular approaches have been used to design probes to identify the cells that express the gene, or to ascertain the rate of expression of the gene, and even to predict the post-translational modifications that can generate functional neuropeptides from a biologically inert precursor. Although the power of these approaches is substantial, it is appreciated that a gene sequence or an mRNA sequence reflects the potential products that may be assembled in a secretory cell. To understand the functional capabilities of the secretory cell, the molecular genetics approaches must be combined with procedures that actually characterize the end-products generated by the secretory cell. Recent advances in two-dimensional gel electrophoresis and mass spectrometry now make it possible to analyze neuropeptides from a relatively small amount of tissue. These procedures can reveal novel end-products, tissue-specific endoproteolytic cleavage events, and developmental shifts in post-translational processing schemes. A gene family that illustrates all of these processes and the advantages of combining genomics with proteomics is the opioid/orphanin gene family.

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Section: Post-translational Processing Mechanismsmentioning

confidence: 99%

Analyzing the evolution of the opioid/orphanin gene family

Dores

Lecaude

Bauer

et al. 2002

Mass Spectrometry Reviews

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“…Alpha-MSH is found in three different N-terminal acetylation isoforms: des-, mono-and di-acetylated aMSH. In mammals, as in most other species where posttranslational acetylation of aMSH occurs, the major form is diacetyl aMSH (Dores et al, 1993;Keller et al, 1994). In a number of fish species, however, including tilapia, the dominant form is mono-acetyl aMSH (Arends et al, 2000;Dores et al, 1993;Lamers et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

“…In a number of fish species, however, including tilapia, the dominant form is mono-acetyl aMSH (Arends et al, 2000;Dores et al, 1993;Lamers et al, 1991). Acetylation modifies the bioactivity of the peptides (Keller et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Alpha-MSH, the melanocortin-1 receptor and background adaptation in the Mozambique tilapia, Oreochromis mossambicus

Salm

Metz

Bonga

et al. 2005

General and Comparative Endocrinology

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The regulation of skin darkness in vertebrates is mediated by alpha-melanophore-stimulating-hormone (alphaMSH). For this action, alphaMSH binds to the melanocortin (MC)-1 receptor, a 7-transmembrane receptor located in melanophore cell membranes. The Mozambique tilapia, Oreochromis mossambicus, can change the hue of its body in response to a change in background, a process that may involve alphaMSH and the MC1R. Scale melanophores were isolated from tilapia that were acclimatised for 25 days to a black, control grey or white background and then tested for their sensitivity to des-, mono-, and di-acetylated alphaMSH. On all backgrounds, mono-acetylated alphaMSH was the dominant isoform present in pituitary homogenates. Mono-acetylated alphaMSH also had the highest potency to disperse melanosomes. Black background adapted fish showed the highest dispersing response to alphaMSH, independent of the isoform applied. We elucidated the nucleotide and amino acid sequence of the tilapia MC1R. We show that its expression in skin does not change when tilapia are acclimatised for 25 days to a black, grey or white background, while a clear change in hue is visible. This finding, combined with the absence of differential MC1R gene expression following background acclimation indicates that the increased sensitivity to alphaMSH is most likely a result of changes in the intracellular signalling system in melanophores of black background adapted fish, rather than up-regulation of the MC1R.

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