Vitellogenin(VTGor less popularly known asVG) (fromLatinvitellus,yolk, andgenero,I produce) is a precursor of egg yolk that transports protein and some lipid from the liver through the blood to the growing oocytes where it becomes part of the yolk. Normally, it is only found in the blood or hemolymph of females, and can therefore be used as a biomarker in vertebrates of exposure to environmental estrogens which stimulate elevated levels in males as well as females.[1]"Vitellogenin" is a synonymous term for the gene and the expressedprotein.The protein product is classified as a glycolipoprotein, having properties of a sugar, fat and protein. It belongs toa family of several lipid transport proteins.

Vitellinogen, open beta-sheet
Identifiers
SymbolDUF1943
PfamPF09172
InterProIPR015255
SCOP21lsh/SCOPe/SUPFAM
Available protein structures:
Pfam structures/ECOD
PDBRCSB PDB;PDBe;PDBj
PDBsumstructure summary

Vitellogenin is anegg yolkprecursor found in the females of nearly alloviparousspecies including fish, amphibians, reptiles, birds, mostinvertebrates,and monotremes.[2]Vitellogenin is the precursor of thelipoproteinsandphosphoproteinsthat make up most of the protein content of yolk. In the presence ofestrogenic endocrine disruptive chemicals(EDCs), male fish can express the gene in adose dependentmanner. Thisgene expressionin male fish can be used as a molecular marker of exposure toestrogenicEDCs.[3]

Function

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Vitellogenin provides the major egg yolkproteinthat is a source ofnutrientsduring earlydevelopmentof egg-laying (oviparous)vertebratesandinvertebrates.Although vitellogenin also carries some lipid for deposition in the yolk, the primary mechanism for deposition of yolk lipid is instead via VLDLs, at least in birds and reptiles.[4]Vitellogenin precursors are multi-domainapolipoproteins(proteins that bind to lipids to form lipoproteins), that are cleaved into distinct yolkproteins.Different vitellogenin proteins exist, which are composed of variable combinations of yolk protein components; however, thecleavagesites areconserved.[citation needed]

Components

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In vertebrates, a complete vitellogenin is composed of:

N-terminal lipid transport domain

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Vitellogenin lipid transport domain, N-terminal
Identifiers
SymbolVitellogenin_N
PfamPF01347
InterProIPR001747
SMARTSM00638
PROSITEPS51211
SCOP21llv/SCOPe/SUPFAM
OPM superfamily254
OPM protein1lsh
Available protein structures:
Pfam structures/ECOD
PDBRCSB PDB;PDBe;PDBj
PDBsumstructure summary

This particular domain represents aconservedregion found in severallipidtransportproteins, including vitellogenin,microsomaltriglyceridetransferproteinand apolipoprotein B-100.[7]

Vesicle trafficking

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This particular domain, the Vitellogenin lipid transport domain, is also found in the Microsomal triglyceride transfer protein (MTTP) and in Apolipoprotein B. It aids cell trafficking and export of cargo.[citation needed]

Microsomal triglyceride transfer protein (MTTP)

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Microsomal triglyceride transfer protein (MTTP) is anendoplasmic reticulumlipid transfer protein involved in thebiosynthesisand lipid loading of apolipoprotein B. MTTP is also involved in the late stage of CD1d trafficking in thelysosomalcompartment, CD1d being the MHC I-like lipidantigenpresentingmolecule.[8]

Apolipoprotein B

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Apolipoprotein B can exist in two forms: B-100 and B-48. Apolipoprotein B-100 is present on several lipoproteins, including verylow-density lipoproteins(VLDL),intermediatedensity lipoproteins (IDL) andlow density lipoproteins(LDL), and can assemble VLDL particles in theliver.[9]Apolipoprotein B-100 has been linked to the development ofatherosclerosis.

ApoB is ancestrally universal to all animals, as homologs are found inchoanoflagellates.The insect homolog is calledapolipophorin I/II.[10]

Human proteins containing this domain

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APOB(see native LDL-ApoB structure at 37°ConYouTube);[11]MTTP;

Honey bees

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Honey beesdeposit vitellogenin molecules in fat bodies in their abdomen and heads. The fat bodies apparently act as a food storage reservoir. The glycolipoprotein vitellogenin has additional functionality as it acts as anantioxidantto prolongQueen beeandforagerlifespan as well as ahormonethat affects future foraging behavior.[12] The health of a honey bee colony is dependent upon the vitellogenin reserves of the nurse bees – the foragers having low levels of vitellogenin. As expendable laborers, the foragers are fed just enough protein to keep them working their risky task of collecting nectar and pollen. Vitellogenin levels are important during the nest stage and thus influence honey bee worker division of labor.[citation needed]

A nurse bee's vitellogenin titer that developed in the first four days after emergence, affects its subsequent age to begin foraging and whether it preferentially forages for nectar or pollen. If young workers are short on food their first days of life, they tend to begin foraging early and preferentially for nectar. If they are moderately fed, they forage at normal age preferentially for nectar. If they are abundantly fed, immediately after emergence, their vitellogenin titer is high and they begin foraging later in life, preferentially collecting pollen. Pollen is the only available protein source for honey bees.[13]

Juvenile hormone feedback loop

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For the majority of the investigated insect species it has been documented that juvenile hormone stimulates the transcription of the vitellogenin genes and the consequent control of vitellogenin production (cf. Engelmann, 1983; Wyatt and Davey, 1996).[14][15]

The vitellogenin expression is part of a regulatory feedback loop that enables vitellogenin andjuvenile hormoneto mutually suppress each other. Vitellogenin and juvenile hormone likely workantagonisticallyin the honey bee to regulate the honey bees development and behavior. Suppression of one leads to hightitersof the other.[16]

It is likely that the balance between vitellogenin and juvenile hormone levels is also involved inswarmingbehavior.[17]

Juvenile hormone levels drop in honey bee colonies pre-swarming and it is expected that vitellogenin levels would therefore rise. One may surmise, that swarming bees would want to pack along as much vitellogenin as possible to extend their lifespan and to be able to quickly build a new nest.[citation needed]

Evolution

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Vertebrates started off with a single copy of the vitellogenin gene, and the bird-mammalian and amphibian lineages each experienced duplications that gave rise to the modern genes. With the exception ofmonotremes,mammals have all their vitellogenin genes turned into pseudogenes, although the regionsyntenicto bird VIT1-VIT2-VIT3 can still be found and aligned.[18]In monotremes just one of the genes remained functional.[19]

See also

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References

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  1. ^"Definition of VITELLOGENIN".
  2. ^Robinson, Richard (18 March 2008)."For Mammals, Loss of Yolk and Gain of Milk Went Hand in Hand".PLOS Biology.6(3): e77.doi:10.1371/journal.pbio.0060077.PMC2267822.PMID20076706.
  3. ^Tran, Thi Kim Anh; Yu, Richard Man Kit; Islam, Rafiquel; Nguyen, Thi Hong Tham; Bui, Thi Lien Ha; Kong, Richard Yuen Chong; O'Connor, Wayne A.; Leusch, Frederic D.L.; Andrew-Priestley, Megan; MacFarlane, Geoff R. (May 2019). "The utility of vitellogenin as a biomarker of estrogenic endocrine disrupting chemicals in molluscs".Environmental Pollution.248:1067–1078.Bibcode:2019EPoll.248.1067T.doi:10.1016/j.envpol.2019.02.056.hdl:10072/386355.PMID31091639.S2CID92464394.
  4. ^Price, E. R. (2017)."The physiology of lipid storage and use in reptiles".Biological Reviews.92(3): 1406–1426.doi:10.1111/brv.12288.PMID27348513.S2CID7570705.
  5. ^Finn, Roderick Nigel (1 June 2007)."Vertebrate Yolk Complexes and the Functional Implications of Phosvitins and Other Subdomains in Vitellogenins1".Biology of Reproduction.76(6): 926–35.doi:10.1095/biolreprod.106.059766.PMID17314313.
  6. ^Thompson, James R.; Banaszak, Leonard J. (July 2002). "Lipid−Protein Interactions in Lipovitellin".Biochemistry.41(30): 9398–409.doi:10.1021/bi025674w.PMID12135361.
  7. ^Anderson TA, Levitt DG, Banaszak LJ (July 1998)."The structural basis of lipid interactions in lipovitellin, a soluble lipoprotein".Structure.6(7): 895–909.doi:10.1016/S0969-2126(98)00091-4.PMID9687371.
  8. ^Sagiv, Yuval; Bai, Li; Wei, Datsen G.; Agami, Reuven; Savage, Paul B.; Teyton, Luc; Bendelac, Albert (16 April 2007)."A distal effect of microsomal triglyceride transfer protein deficiency on the lysosomal recycling of CD1d".The Journal of Experimental Medicine.204(4): 921–8.doi:10.1084/jem.20061568.PMC2118556.PMID17403933.
  9. ^Olofsson SO, Borèn J (November 2005)."Apolipoprotein B: a clinically important apolipoprotein which assembles atherogenic lipoproteins and promotes the development of atherosclerosis".Journal of Internal Medicine.258(5): 395–410.doi:10.1111/j.1365-2796.2005.01556.x.PMID16238675.S2CID19885776.
  10. ^Huebbe P, Rimbach G (August 2017). "Evolution of human apolipoprotein E (APOE) isoforms: Gene structure, protein function and interaction with dietary factors".Ageing Research Reviews.37:146–161.doi:10.1016/j.arr.2017.06.002.PMID28647612.S2CID3758905.
  11. ^Kumar V, Butcher SJ, Öörni K, Engelhardt P, Heikkonen J, et al. (2011) Three-Dimensional cryoEM Reconstruction of Native LDL Particles to 16Å Resolution at Physiological Body Temperature.[1]
  12. ^Oliver, Randy (August 2007). "Fat Bees Part 1".American Bee Journal.[verification needed]
  13. ^Randy, Oliver (Aug 2007)."Fat Bees - Part 1".American Bee Journal:714.
  14. ^Engelmann F (1983). "Vitellogenesis controlled by juvenile hormone". In Downer RG, Laufer H (eds.).Endocrinology of Insects.New York: Alan R. Liss. pp. 259–270.
  15. ^Wyatt GR, Davey KG (1996). "Cellular and Molecular Actions of Juvenile Hormone. II. Roles of Juvenile Hormone in Adult Insects".Advances in Insect Physiology Volume 26.Vol. 26. pp. 1–155.doi:10.1016/S0065-2806(08)60030-2.ISBN9780120242269.
  16. ^Hrassnigg, Norbert; Crailsheim, Karl (2005)."Differences in drone and worker physiology in honeybees (Apis mellifera) "(PDF).Apidologie.36(2): 255–277.doi:10.1051/apido:2005015.
  17. ^Zeng, Zhijiang; Huang, Zachary Y.; Qin, Yuchuan; Pang, Huizhong (1 April 2005)."Hemolymph Juvenile Hormone Titers in Worker Honey Bees under Normal and Preswarming Conditions".Journal of Economic Entomology.98(2): 274–278.doi:10.1603/0022-0493-98.2.274.PMID15889713.S2CID198130721.
  18. ^Brawand, David; Wahli, Walter; Kaessmann, Henrik; Phillippe, Hervé (18 March 2008)."Loss of Egg Yolk Genes in Mammals and the Origin of Lactation and Placentation".PLOS Biology.6(3): e63.doi:10.1371/journal.pbio.0060063.PMC2267819.PMID18351802.
  19. ^Yang Zhou, Linda Shearwin-Whyatt, Guojie Zhanget al.:Platypus and echidna genomes reveal mammalian biology and evolution.In:Nature.6 January 2021.doi:10.1038/s41586-020-03039-0.See also:

Further reading

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This article incorporates text from the public domainPfamandInterPro:IPR001747