Human complement factor B: cDNA cloning, nucleotide sequencing, phenotypic conversion by site-directed mutagenesis and expression.
A full-length cDNA clone, BHL4-1, encoding factor B was isolated from a human liver cDNA library and sequenced in its entirety. It consists of 2388 bp which include a 5'-untranslated region of 40 bp, a single open reading frame, 2292 bp in length, and a 3'-untranslated region of 56 bp followed by a poly-A tail. The deduced amino acid sequence comprises 25 residues of a putative leader peptide and 739 residues of the mature polypeptide chain of the F allele of factor B. We constructed an S allele-like Q7R mutant of BHL4-1 by site-directed mutagenesis. Both the wild-type and mutant factor B cDNA were expressed transiently in a eukaryotic system. The specific hemolytic activities of the two recombinant factor B alleles and of native B were not significantly different from each other.
Horiuchi
T
T
First Department of Internal Medicine, School of Medicine, Ehime University, Japan.
Kim
S
S
Matsumoto
M
M
Watanabe
I
I
Fujita
S
S
Volanakis
J E
JE
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D003167:Complement Activation; D003175:Complement C2 / Q000235:genetics*; D050577:Complement C3-C5 Convertases / Q000235:genetics; D011415:Complement Factor B / Q000235:genetics* / Q000302:isolation & purification; D018076:DNA, Complementary / Q000302:isolation & purification; D015870:Gene Expression; D006801:Humans; D008099:Liver / Q000737:chemistry; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010641:Phenotype; D017422:Sequence Analysis, DNA
D003175:Complement C2; D018076:DNA, Complementary; D050577:Complement C3-C5 Convertases; D011415:Complement Factor B