Molecular cloning and characterization of novel splicing variants of human decay-accelerating factor.
Decay-accelerating factor (DAF) is one of the complement regulatory proteins. Two isoforms of DAF have been identified in humans. In this study, we isolated novel cDNAs encoding five isoforms of DAF from the human lung, which were generated by insertion of new exonic sequences. RT-PCR revealed that all isoforms were expressed in almost all tissues tested, although the expression patterns and levels differed among the tissues. Transfection of isoform vDAF1, 2, and 3 cDNAs into CHO cells showed that these molecules are soluble forms secreted after glycosylation. Isoform vDAF4 and vDAF5 cDNAs included a part of and the entire intron 7 sequence, respectively, and the transfection of vDAF4 cDNA produced a large, glycosylated, membrane-bound form. These results suggest that more than seven isoforms of human DAF are involved in the regulation of complement activation under physiological conditions through their specific structures and localization.
Osuka
Fumihiko
F
Department of Surgery I, Fukushima Medical University School of Medicine, 1-Hikariga-oka, Fukushima 960-1295, Japan.
Endo
Yuichi
Y
Higuchi
Mitsunori
M
Suzuki
Hiroyuki
H
Shio
Yutaka
Y
Fujiu
Koichi
K
Kanno
Ryuzo
R
Oishi
Akio
A
Terashima
Masanori
M
Fujita
Teizo
T
Gotoh
Mitsukazu
M
D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D018958:CD55 Antigens / Q000235:genetics*; D016466:CHO Cells; D003001:Cloning, Molecular; D003167:Complement Activation / Q000235:genetics*; D006224:Cricetinae; D003412:Cricetulus; D018076:DNA, Complementary / Q000235:genetics*; D006801:Humans; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000235:genetics
D018958:CD55 Antigens; D018076:DNA, Complementary; D020033:Protein Isoforms