The Xenopus Oocyte as an Expression System for Functional Analyses of Fish Aquaporins

Chauvigné, François; Ferré, Alba; Cerdà, Joan

doi:10.1007/978-1-0716-0970-5_2

Cited by 6 publications

(4 citation statements)

References 36 publications

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“…To determine whether the TSA1C paralogs from each model species encode functional water channels, we used oocytes from X. laevis as standard surrogate experimental systems for the fish oocytes ( Chauvigné et al 2021 ). Oocytes were injected with the corresponding cRNAs, synthesized from nontagged or human influenza hemagglutinin (HA)-tagged cDNAs, or with water as negative controls, and subsequently submitted to swelling assays ( fig.…”

Section: Resultsmentioning

confidence: 99%

Functional Evolution of Clustered Aquaporin Genes Reveals Insights into the Oceanic Success of Teleost Eggs

Ferré

Chauvigné

Vlasova

et al. 2023

Molecular Biology and Evolution

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Aquaporin-mediated oocyte hydration is considered important for the evolution of pelagic eggs and the radiative success of marine teleosts. However, the molecular regulatory mechanisms controlling this vital process are not fully understood. Here, we analyzed >400 piscine genomes to uncover a previously unknown teleost-specific aquaporin-1 cluster (TSA1C) comprised of tandemly arranged aqp1aa-aqp1ab2-aqp1ab1 genes. Functional evolutionary analysis of the TSA1C reveals a ∼300-million-year history of downstream aqp1ab-type gene loss, neofunctionalization and subfunctionalization, but with marine species that spawn highly hydrated pelagic eggs almost exclusively retaining at least one of the downstream paralogs. Unexpectedly, one third of the modern marine euacanthomorph teleosts selectively retain both aqp1ab-type channels, and co-evolved protein kinase-mediated phosphorylation sites in the intracellular subdomains together with teleost-specific Ywhaz-like (14-3-3ζ-like) binding proteins for co-operative membrane trafficking regulation. To understand the selective evolutionary advantages of these mechanisms, we show that a two-step regulated channel shunt avoids competitive occupancy of the same plasma membrane space in the oocyte and accelerates hydration. These data suggest that the evolution of the adaptive molecular regulatory features of the TSA1C facilitated the rise of pelagic eggs and their subsequent geodispersal in the oceanic currents.

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Section: Resultsmentioning

confidence: 99%

Functional Evolution of Clustered Aquaporin Genes Reveals Insights into the Oceanic Success of Teleost Eggs

Ferré

Chauvigné

Vlasova

et al. 2023

Molecular Biology and Evolution

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“…The cRNAs corresponding to the different constructs were synthesized in vitro with T7 RNA polymerase from Xba I-digested pT7Ts vector containing the cDNAs. The isolation and microinjection of oocytes, and subsequent swelling assays, were carried out as previously described ( 63 ). Oocytes were injected with 50 nl of water alone (controls) or containing 15 ng of Avpr1aa, Avpr2aa or Oxtrb cRNAs.…”

Section: Methodsmentioning

confidence: 99%

Neurohypophysial and paracrine vasopressinergic signaling regulates aquaporin trafficking to hydrate marine teleost oocytes

Ferré,

Chauvigné,

Gozdowska

et al. 2023

Front. Endocrinol.

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The dual aquaporin (Aqp1ab1/Aqp1ab2)-mediated hydration of marine teleost eggs, which occurs during oocyte meiosis resumption (maturation), is considered a key adaptation underpinning their evolutionary success in the oceans. However, the endocrine signals controlling this mechanism are almost unknown. Here, we investigated whether the nonapeptides arginine vasopressin (Avp, formerly vasotocin) and oxytocin (Oxt, formerly isotocin) are involved in marine teleost oocyte hydration using the gilthead seabream (Sparus aurata) as a model. We show that concomitant with an increased systemic production of Avp and Oxt, the nonapeptides are also produced and accumulated locally in the ovarian follicles during oocyte maturation and hydration. Functional characterization of representative Avp and Oxt receptor subtypes indicates that Avpr1aa and Oxtrb, expressed in the postvitellogenic oocyte, activate phospholipase C and protein kinase C pathways, while Avpr2aa, which is highly expressed in the oocyte and in the follicular theca and granulosa cells, activates the cAMP-protein kinase A (PKA) cascade. Using ex vivo, in vitro and mutagenesis approaches, we determined that Avpr2aa plays a major role in the PKA-mediated phosphorylation of the aquaporin subdomains driving membrane insertion of Aqp1ab2 in the theca and granulosa cells, and of Aqp1ab1 and Aqp1ab2 in the distal and proximal regions of the oocyte microvilli, respectively. The data further indicate that luteinizing hormone, which surges during oocyte maturation, induces the synthesis of Avp in the granulosa cells via progestin production and the nuclear progestin receptor. Collectively, our data suggest that both the neurohypophysial and paracrine vasopressinergic systems integrate to differentially regulate the trafficking of the Aqp1ab-type paralogs via a common Avp-Avpr2aa-PKA pathway to avoid competitive occupancy of the same plasma membrane space and maximize water influx during oocyte hydration.

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“…The cRNAs were synthesized in vitro with T7 RNA polymerase from XbaI-digested pT7Ts. The isolation and microinjection of oocytes, as well as the swelling assays, were carried out as previously described [40]. The oocytes were injected with…”

Section: Microinjection Of X Laevis Oocytes and Swelling Assaysmentioning

confidence: 99%

Aquaporin splice variation differentially modulates channel function during marine teleost egg hydration

Ferré,

Chauvigné,

Zapater

et al. 2023

PLoS ONE

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Aquaporin-mediated oocyte hydration is a developmentally regulated adaptive mechanism that co-occurs with meiosis resumption in marine teleosts. It provides the early embryos with vital water until osmoregulatory systems develop, and in the majority of marine teleosts causes their eggs to float. Recent studies have shown that the subdomains of two water channels (Aqp1ab1 and Aqp1ab2) encoded in a teleost-specific aquaporin-1 cluster (TSA1C) co-evolved with duplicated Ywhaz-like (14-3-3ζ-like) binding proteins to differentially control their membrane trafficking for maximal egg hydration. Here, we report that in species that encode the full TSA1C, in-frame intronic splice variants of Aqp1ab1 result in truncated proteins that cause dominant-negative inhibition of the canonical channel trafficking to the plasma membrane. The inhibition likely occurs through hetero-oligomerization and retention in the endoplasmic reticulum (ER) and ultimate degradation. Conversely, in species that only encode the Aqp1ab2 channel we found an in-frame intronic splice variant that results in an intact protein with an extended extracellular loop E, and an out-of frame intronic splice variant with exon readthrough that results in a truncated protein. Both isoforms cause dominant-negative enhancement of the degradation pathway. However, the extended and truncated Aqp1ab2-type variants can also partially escape from the ER to reach the oocyte plasma membrane, where they dominantly-negatively inhibit water flux. The ovarian follicular expression ratios of the Aqp1ab2 isoforms in relation to the canonical channel are lowest during oocyte hydration, but subsequently highest when the canonical channel is recycled, thus leaving the eggs endowed with >90% water. These findings suggest that the expression of inhibitory isoforms of Aqp1ab1 and Aqp1ab2 may represent a new regulatory mechanism through which the cell-surface expression and the activity of the canonical channels can be physiologically modulated during oocyte hydration in marine teleosts.

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The Xenopus Oocyte as an Expression System for Functional Analyses of Fish Aquaporins

Cited by 6 publications

References 36 publications

Functional Evolution of Clustered Aquaporin Genes Reveals Insights into the Oceanic Success of Teleost Eggs

Functional Evolution of Clustered Aquaporin Genes Reveals Insights into the Oceanic Success of Teleost Eggs

Neurohypophysial and paracrine vasopressinergic signaling regulates aquaporin trafficking to hydrate marine teleost oocytes

Aquaporin splice variation differentially modulates channel function during marine teleost egg hydration

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