Identification and sequence analysis of four complement factor H-related transcripts in mouse liver.
Mouse liver RNA analyzed by Northern blotting with a full-length complement factor H cDNA probe demonstrates the 4.4-kilobase (kb) H mRNA as well as three additional hybridizing species of 3.5, 2.8, and 1.8 kb, respectively. Further characterization of these alternative transcripts was pursued by isolation of additional cDNAs from a liver library using a full-length H probe. Twelve clones homologous to but distinct from H were isolated, analyzed by restriction mapping, and divided into four classes, A, B, C, and D, based on their sequences. Clones from classes A, B, and C all contained nearly identical 5'-untranslated regions and leader sequences that differed from H at more than 50% of their nucleotide positions. The 5'-untranslated and leader sequences of the class D clone were unrelated to the corresponding regions of H or the class A, B, or C clones. The remaining portions of the H-related cDNAs were made up of short consensus repeats, 7 in class A, 4 in class B, 13 in class C, and 5 in class D. To determine the relationship between the H-related transcripts and the cDNA clones, Northern blots of liver RNA were analyzed by hybridization with two probes, one specific for the class D cDNA and the other reacting specifically with the class A, B, and C cDNAs. The class A/B/C probe detected transcripts of 3.5, 2.8, and 1.8 kb in liver RNA, and the class D probe hybridized to a distinct 1.8-kb message. Additionally, a cosmid genomic library was screened with H cDNA, and nine H-related clones were isolated. They spanned a region of approximately 120 kb, defining at least two discrete H-related gene loci. These results identify new members of the super-family of C3b/C4b binding protein genes.
Department of Immunology, Research Institute of Scripps Clinic, La Jolla, California 92037.
D P
DP
Vik
P
P
Muñoz-Cánoves
H
H
Kozono
L G
LG
Martin
B F
BF
Tack
D D
DD
Chaplin
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D003180:Complement C3b Inactivator Proteins / Q000235:genetics*; D017242:Complement Factor H; D003360:Cosmids; D015342:DNA Probes; D008099:Liver / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
D003180:Complement C3b Inactivator Proteins; D015342:DNA Probes; D012333:RNA, Messenger; D012313:RNA; D017242:Complement Factor H