Isolation of a hagfish gene that encodes a complement component.
It has been widely accepted that cyclostomes are the most primitive vertebrates extant with the ability to produce antibodies. We isolated cDNA clones that encode a putative 'antibody' from one of the cyclostomes, Eptatretus burgeri. The amino acid sequence predicted from the nucleotide sequences of the cDNA clones indicated that this gene does actually encode the proteins isolated as hagfish 'antibodies' by various investigators. However, these proteins are not similar to mammalian immunoglobulins but have some characteristics common to complements C3, C4 and C5 in higher vertebrates. We discuss the relationships of the isolated gene for hagfish complement with the mammalian genes for complements C3, C4 and C5. We also discuss the possibility of the presence of antibodies in cyclostomes.
Institute for Comprehensive Medical Science, Fujita Health University, Aichi, Japan.
H
H
Ishiguro
K
K
Kobayashi
M
M
Suzuki
K
K
Titani
S
S
Tomonaga
Y
Y
Kurosawa
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D015152:Blotting, Northern; D015139:Blotting, Southern; D003165:Complement System Proteins / Q000235:genetics*; D004247:DNA / Q000235:genetics; D006196:Hagfishes / Q000235:genetics*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012313:RNA / Q000235:genetics; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D012313:RNA; D003165:Complement System Proteins; D004247:DNA