title: Complement component C3 transcription in Atlantic halibut (Hippoglossus hippoglossus L.) larvae.
abstract: The complement systems of fish are well developed and play an important role in the innate immune response. Complement C3 is the central protein of all three activation pathways and is the major opsonin of the complement system and essential for the generation of the membrane attack complex. A 1548 bp part of complement component C3 was isolated from a halibut liver cDNA library by immunoscreening. The deduced amino acid sequence showed that this part of halibut C3 contained key amino acids for factor H, I and properdin binding as well as two N-glycosylation sites. Digoxigenine labelled mRNA probes were synthesised and the transcription of C3 was monitored in three larval stages at 206, 430 and 1000 degrees d (30, 50 and 99 days post hatching), by in situ hybridisation. C3 mRNA was detected in muscle, liver, brain, chondrocytes, spinal cord, eye, intestines, oesophagus and kidney. These findings are in accordance with a former immunohistochemical study on halibut C3 protein ontogeny, indicating that C3 is indeed locally expressed in many organs from the youngest stages on. Complement may thus be linked to the formation and generation of different organs during development and play an important role in the early immune response of halibut larvae.
authors.affiliation: Institute for Experimental Pathology, University of Iceland, Keldur, IS-112 Reykjavík, Iceland. sigrunl@hi.is
authors.forename: Sigrun
authors.initials: S
authors.lastname: Lange
authors.forename: Slavko H
authors.initials: SH
authors.lastname: Bambir
authors.forename: Alister W
authors.initials: AW
authors.lastname: Dodds
authors.forename: Tim
authors.initials: T
authors.lastname: Bowden
authors.forename: Ian
authors.initials: I
authors.lastname: Bricknell
authors.forename: Sigrun
authors.initials: S
authors.lastname: Espelid
authors.forename: Bergljót
authors.initials: B
authors.lastname: Magnadóttir
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003176:Complement C3 / Q000235:genetics / Q000378:metabolism*; D005432:Flounder / Q000235:genetics* / Q000276:immunology*; D015723:Gene Library; D017403:In Situ Hybridization; D007814:Larva / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D016415:Sequence Alignment
chemical_list: D003176:Complement C3