γ-Glutamyl transpeptidase in hydra

Danner, Jean; Lenhoff, Howard M.; Houston-Cobb, M.; Heagy, Wyrta; Marshall, Garland R.

doi:10.1016/0006-291x(76)90513-1

Cited by 11 publications

(10 citation statements)

References 16 publications

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“…Could they be the same protein? Next we analyzed hydra for this enzyme (56,88). We found it present in significant concentrations (see also 89), and its requirement for amino acid acceptors similar to that reported for the same enzyme activity as found elsewhere (56,88).…”

Section: Summary and Future Directionssupporting

confidence: 70%

Aquatic Invertebrates: Model Systems for Study of Receptor Activation and Evolution of Receptor Proteins

Lenhoff¹,

Heagy²

1977

Annu. Rev. Pharmacol. Toxicol.

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Section: Summary and Future Directionssupporting

confidence: 70%

Aquatic Invertebrates: Model Systems for Study of Receptor Activation and Evolution of Receptor Proteins

Lenhoff¹,

Heagy²

1977

Annu. Rev. Pharmacol. Toxicol.

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“…This final step of cnidocyst maturation requires the synthesis of poly-γ-glutamate by enzymes found within the developing capsule [ 12 – 14 ]. The enzyme thought to be responsible for the synthesis of poly-γ-glutamate, γ-glutamyl transpeptidase ( Ggt ), has been isolated from discharged cnidocytes from hydrozoan, anthozoan, and cubozoan lineages, suggesting that Ggt may also be a ubiquitous marker of cnidocytes [ 7 , 13 , 15 , 16 ]. Further surveys of gene and protein expression in cnidocytes from across cnidarians have revealed that these novel cells are highly heterogeneous, expressing both novel (cnidarian-specific) and conserved genes [ 7 , 9 , 15 , 17 – 20 ].…”

Section: Introductionmentioning

confidence: 99%

PaxA, but not PaxC, is required for cnidocyte development in the sea anemone Nematostella vectensis

Babonis

Martindale

2017

EvoDevo

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Background Pax genes are a family of conserved transcription factors that regulate many aspects of developmental morphogenesis, notably the development of ectodermal sensory structures including eyes. Nematostella vectensis, the starlet sea anemone, has numerous Pax orthologs, many of which are expressed early during embryogenesis. The function of Pax genes in this eyeless cnidarian is unknown.ResultsHere, we show that PaxA, but not PaxC, plays a critical role in the development of cnidocytes in N. vectensis. Knockdown of PaxA results in a loss of developing cnidocytes and downregulation of numerous cnidocyte-specific genes, including a variant of the transcription factor Mef2. We also demonstrate that the co-expression of Mef2 in a subset of the PaxA-expressing cells is associated with the development with a second lineage of cnidocytes and show that knockdown of the neural progenitor gene SoxB2 results in downregulation of expression of PaxA, Mef2, and several cnidocyte-specific genes. Because PaxA is not co-expressed with SoxB2 at any time during cnidocyte development, we propose a simple model for cnidogenesis whereby a SoxB2-expressing progenitor cell population undergoes division to give rise to PaxA-expressing cnidocytes, some of which also express Mef2.DiscussionThe role of PaxA in cnidocyte development among hydrozoans has not been studied, but the conserved role of SoxB2 in regulating the fate of a progenitor cell that gives rise to neurons and cnidocytes in Nematostella and Hydractinia echinata suggests that this SoxB2/PaxA pathway may well be conserved across cnidarians.

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“…Laboratory-reared specimens of Hydra attenuata were cultured and treated with rifampicin as described by Danner et al (1976) and then homogenized (Teflon/glass) in 10mM-Tris/HCl, pH9, containing lOmM-MgCl2. After a 3min centrifugation at 1000g the supernatant was either dialysed against the extraction buffer at 4°C for 18-24h (fraction SI) or it was centrifuged at 12000g for 20-30min and the sediment was resuspended in the homogenization medium (fraction P2).…”

Section: Methodsmentioning

confidence: 99%

“…y-Glutamyltransferase (EC 2.3.2.2), first discovered by Hanes et al (1950), has been a subject of study in many organisms [see Meister (1974) for a review]. More recently, knowledge of this enzyme has been extended to another phylum by reports on y-glutamyltransferase activity in two species of the fresh-water cnidarian hydra (Danner et al, 1976;Tate & Meister, 1976).…”

mentioning

confidence: 99%

“…Previous studies with GSH analogues in which cysteine (position 2) was either altered or replaced showed that the thiol group was not a requirement of the transferase substrates (Tate & Meister, 1974. There were no reports on GSH analogues in which glycine (position 3) was replaced by other amino acids until the one describing activity in Hydra attenuata (Danner et al, 1976) appeared. The data from these experiments suggested that analogues containing leucine or tyrosine in position 3 bound less well to the enzyme compared with those containing glycine in that position, but the data did not provide a rationale for the apparent decrease in binding.…”

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confidence: 99%

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Interaction of glutathione analogues with Hydra attenuata γ-glutamyltransferase

Danner¹,

Cobb²,

Heagy³

et al. 1978

Biochemical Journal

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gamma-Glutamyltransferase activity was studied in extracts of the cnidarian Hydra attenuata. The binding of gamma-glutamyl peptide analogues to the enzyme was studied by observing their effects on heat denaturation and their inhibition of p-nitroaniline release from gamma-glutamyl p-nitroanilide. Neither position-1 analogues, in which the gamma-glutamyl moiety was changed to a beta-aspartyl (beta-Asp-Abu-Gly) or an alpha-glutamyl (Glu-Abu-Gly) linkage, nor glutamate protected the enzyme against inactivation at 58 degrees C. GSH (reduced glutathione), gamma-Glu-Abu-Gly and gamma-Glu-Met on the other hand did prevent heat denaturation. GSH and analogues of GSH were competitive inhibitors of p-nitroaniline release, but those analogues in which glycine was replaced by 2-aminoisobutyrate, phenylalanine, leucine or tyrosine had Ki values that were approximately five times those of analogues with the cysteine residue replaced.

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γ-Glutamyl transpeptidase in hydra

Cited by 11 publications

References 16 publications

Aquatic Invertebrates: Model Systems for Study of Receptor Activation and Evolution of Receptor Proteins

Aquatic Invertebrates: Model Systems for Study of Receptor Activation and Evolution of Receptor Proteins

PaxA, but not PaxC, is required for cnidocyte development in the sea anemone Nematostella vectensis

Interaction of glutathione analogues with Hydra attenuata γ-glutamyltransferase

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