Molecular chaperones, stress resistance and development in Artemia franciscana.
Embryos of the brine shrimp, Artemia franciscana, either develop directly into swimming larvae or are released from females as encysted gastrulae (cysts) which enter diapause, a reversible state of dormancy. Metabolic activity in diapause cysts is very low and these embryos are remarkably resistant to physiological stresses. Encysting embryos, but not those undergoing uninterrupted development, synthesize large amounts of two proteins, namely p26 and artemin. Cloning and sequencing demonstrated p26 is a small heat shock/alpha-crystallin protein while artemin has structural similarity to ferritin. p26 exhibits molecular chaperone activity in vitro, moves reversibly into nuclei during stress and confers thermotolerance on transformed organisms, suggesting critical roles in cyst development. The function of artemin is unknown. Encysted Artemia also contain an abundance of trehalose, a disaccharide capable of protecting embryos. Artemia represent a novel experimental system where the developmental functions of small heat shock/alpha-crystallin proteins and other stress response elements can be explored.
MacRae
Thomas H
TH
Department of Biology, Dalhousie University, Halifax, NS, Canada B3H 4J1. tmacrae@dal.ca
D000595:Amino Acid Sequence; D000818:Animals; D001156:Artemia / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D060829:Arthropod Proteins; D002352:Carrier Proteins; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development; D005293:Ferritins / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018869:Heat-Shock Response / Q000502:physiology*; D033862:Iron-Binding Proteins; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins; D016415:Sequence Alignment
D060829:Arthropod Proteins; D002352:Carrier Proteins; D006360:Heat-Shock Proteins; D033862:Iron-Binding Proteins; D018832:Molecular Chaperones; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; C490888:artemin protein, brine shrimp; C107632:p26 chaperone protein, Artemia franciscana; D005293:Ferritins