Lipophorin as a yolk precursor in <i>Hyalophora cecropia</i>: Uptake kinetics and competition with vitellogenin

Kulakosky, Peter C.; Telfer, William H.

doi:10.1002/arch.940140406

Cited by 41 publications

(18 citation statements)

References 25 publications

(27 reference statements)

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“…Only a small fraction (10% of egg lipids) has been found to originate from the combined cellular uptake of vitellogenin and the high-density (less lipidated) form of lipophorin . Similarly, the uptake of lipophorin by developing oocytes has been demonstrated in the saturniid moths Philosamia cynthia (Chino et al 1977) and Hyalophora cecropia (Kulakosky and Telfer 1990;Telfer et al 1991). The competition for cellular uptake between vitellogenin and high-density lipophorin in H. cecropia was initially explained by the presence of a common receptor for these two lipoproteins (Kulakosky and Telfer 1990).…”

Section: Discussionmentioning

confidence: 94%

“…The hen oocyte vitellogenin receptor has an affinity for the mammalian lipoproteins (Steyrer et al 1990;Warrier and Subramoniam 2002 and references cited therein), and in a crab, the vitellogenin receptor has even been found to recognize mammalian lipoprotein (Warrier and Subramoniam 2002). In insects, both lipoproteins have been speculated to be incorporated by the same receptor, with the higher affinity of this receptor for the yolk protein possibly leading to a preferential uptake of vitellogenin as the main storage protein of the oocyte (Kulakosky and Telfer 1990). On the other hand, the incorporation of yolk protein into the oocyte of the polychaete N. virens is not inhibited by male coelomic fluid (Fischer and Rabien 1986), despite its known content of lipoprotein, which has been characterized as a discoidal high-density lipoprotein (see Schenk et al 2006).…”

Section: Introductionmentioning

confidence: 94%

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Lipoprotein mediated lipid uptake in oocytes of polychaetes (Annelida)

Schenk

Hoeger

2009

Cell Tissue Res

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The uptake of the 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-labeled sex-unspecific Nereis lipoprotein was investigated in oocytes of the nereidid polychaetes Nereis virens and Platynereis dumerilii. The fluorescence label was first observed in endocytic vesicles (<1 microm diameter), which later fused to larger vesicles (2-3 microm); these were finally incorporated into existing unlabeled yolk granules (5-6 microm). In Platynereis oocytes, the fusion of endocytic vesicles was delayed in oocytes at their final stage of development compared with those at an early stage of development. Lipoprotein double-labeled with fluorescein isothiocyanate (FITC) and DiI revealed that both the protein and the lipid moiety remained co-localized during incorporation into the yolk granules of the oocyte. No labeling of the cytoplasmic lipid droplets was observed. In N. virens, unlabeled Nereis lipoprotein was effective as a competitive inhibitor of DiI-labeled Nereis lipoprotein. Ligand blot experiments demonstrated the presence of a lipoprotein receptor with an apparent molecular mass of 120 kDa, which is different from that of the known yolk protein receptor. This indicates the presence, in the polychaete oocyte, of two distinct receptors mediating yolk protein and lipoprotein uptake, respectively. Thus, the sex-unspecific lipoprotein contributes to the lipid supply of the growing oocyte in addition to the known uptake of the yolk-protein-associated lipids. The absence of label in the cytoplasmic lipid droplets, even after prolonged incubation with labeled lipoprotein, suggests that these lipids arise either by the breakdown and resynthesis of lipoprotein-derived lipids and/or by de novo synthesis within the oocyte.

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Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 94%

Lipoprotein mediated lipid uptake in oocytes of polychaetes (Annelida)

Schenk

Hoeger

2009

Cell Tissue Res

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“…AaVgR differs from DmYPR in having more potential phosphorylation sites, with only 26% of them in conserved positions (Fig. 3) nalized by a single receptor in the oocytes of a moth, Hyalophora cecropia (41).…”

Section: Methodsmentioning

confidence: 99%

Molecular characterization of the mosquito vitellogenin receptor reveals unexpected high homology to the Drosophila yolk protein receptor.

Sappington

Kokoza

Cho

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

112

137

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The mosquito (Aedes aegypti) vitellogenin receptor (AaVgR) is a large membrane-bound protein (214 kDa when linearized) that mediates internalization of vitellogenin, the major yolk-protein precursor, by oocytes during egg development. We have cloned and sequenced two cDNA fragments encompassing the entire coding region of AaVgR mRNA, to our knowledge the first insect VgR sequence to be reported. The 7.3-kb AaVgR mRNA is present only in female germ-line cells and is abundant in previtellogenic oocytes, suggesting that the AaVgR gene is expressed early in oocyte differentiation. The deduced amino acid sequence predicts a 202.7-kDa protein before posttranslational processing. The AaVgR is a member of the low density lipoprotein receptor superfamily, sharing significant homology with the chicken (Gallus gallus) VgR and particularly the Drosophila melanogaster yolk protein receptor, in spite of a very different ligand for the latter. Distance-based phylogenetic analyses suggest that the insect VgRIyolk protein receptor lineage and the vertebrate VgR/low density lipoprotein receptor lineage diverged before the bifurcation of nematode and deuterostome lines.The developing embryo of an oviparous animal draws practically all of its requisite nutrients from a cache of proteins, lipids, and carbohydrates stored within the egg as yolk. Yolkprotein precursors are synthesized extraovarially and transported to the developing egg where they are specifically recognized and bound by membrane-spanning cell-surface receptors. Receptor-ligand complexes accumulate in clathrincoated pits, which pinch-off into the cytoplasm, a fundamental process ubiquitous among cells for internalizing macromolecules referred to as receptor-mediated endocytosis (1, 2). The insect oocyte provides an excellent system for studying receptor-mediated endocytosis because of the high intensity of protein uptake. Mosquitoes are especially useful models in this regard, because a tightly regulated series of physiological events associated with egg maturation is synchronized across all primary oocytes by a blood meal.In the yellow fever mosquito Aedes aegypti (Aa), oocyte size increases more than 300-fold within 36 h of a blood meal (3), largely through the specific accumulation of the major yolkprotein precursor vitellogenin (AaVg). This impressive biological feat depends on the proper interaction ofAaVg with its receptor (AaVgR) on the oocyte surface. In addition to its exceptional value as a model for studying receptor-mediated endocytosis, this system is also a promising target for future novel control strategies. For example, interruption of the receptor-ligand interaction would block egg development, and theAaVgR could serve as a target for an antimosquito vaccine (4). A prerequisite to successful manipulation of this system is a thorough understanding of the proteins involved: their structures, interactions, regulation, and expression. Meaningful progress on all of these fronts hinges on knowledge of the primary structures of both AaVg, which we r...

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“…Labeled hemolymph proteins other than hexamerins included vitellogenin and lipophorin (Table 2), which must have been newly synthesized from hydrolytic products of the hexamerins. These two proteins are known to be synthesized during mid to late pharate adult development (Pan, 1971;Kulakosky and Telfer, 1990), and were presumably in transit to the ovaries, where they accounted for 80-90% of the label that was precipitated by TCA from yolk.…”

Section: Clearing Of Labeled Hexamerins From Developing Adult Hemolymphmentioning

confidence: 99%

Equivalence of riboflavin-binding hexamerin and arylphorin as reserves for adult development in two saturniid moths

Pan

Telfer

1999

Arch. Insect Biochem. Physiol.

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The riboflavin‐binding hexamerin (RbH) and arylphorin (ArH) were compared as storage reservoirs for adult development in Hyalophora cecropia. The two hexamerins were metabolically labeled with [3H]leucine and [35S]methionine, isolated by column chromatography, and separately injected into pupae whose diapause had been terminated by chilling. By the time of eclosion at least 98% of both hexamerins had been cleared from the hemolymph. Every reproductive and somatic tissue tested contained trichloroacetic acid‐precipitable label; consistent differences between the two hexamerins were not detected in the distribution of their label to these tissues. While incorporation of intact hexamerins was not ruled out, hydrolysis and reincorporation of the liberated amino acids were indicated by label in vitellogenin and lipophorin, and by differences in 35S/3H ratios, which ranged from over 1.0 in chorions to 0.4 in wings, as compared with 0.75 in the injected hexamerins. Injection of [35S,3H]RbH from H. cecropia into A. luna, a species in the same subfamily whose pupae lack this hexamerin, resulted in a pattern of isotope incorporation similar to that yielded by RbH in the donor species. In neither species was there indication of a developing adult tissue that distinguished between RbH and ArH as precursor reservoirs for morphogenesis. This equivalence helps explain how many species of Lepidoptera are able to complete metamorphosis and reproduce without expressing an RbH gene. Evidence is also presented that ArH stored in the fat body protein granules during pupation may be utilized differently from that remaining in pupal hemolymph. Arch. Insect Biochem. Physiol. 42:138–146, 1999. © 1999 Wiley‐Liss, Inc.

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Lipophorin as a yolk precursor in Hyalophora cecropia: Uptake kinetics and competition with vitellogenin

Cited by 41 publications

References 25 publications

Lipoprotein mediated lipid uptake in oocytes of polychaetes (Annelida)

Lipoprotein mediated lipid uptake in oocytes of polychaetes (Annelida)

Molecular characterization of the mosquito vitellogenin receptor reveals unexpected high homology to the Drosophila yolk protein receptor.

Equivalence of riboflavin-binding hexamerin and arylphorin as reserves for adult development in two saturniid moths

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