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The human C4b-binding protein beta-chain gene

Hillarp, A LU ; Pardo-Manuel, F ; Ruiz, R R ; Rodriguez de Cordoba, S and Dahlbäck, B LU (1993) In The Journal of biological chemistry 268(20). p.23-15017
Abstract

Human complement component C4b-binding protein (C4BP) is composed of seven alpha-chains and one beta-chain. The alpha- and beta-chains are homologous and both contain multiple copies of short consensus repeats (SCR) and in addition carboxyl-terminal non-repeat regions. Each of the alpha-chains contains a binding site for C4b, whereas the beta-chain binds protein S, a vitamin K-dependent protein involved in the regulation of blood coagulation. The alpha- and beta-chain genes are closely linked in the regulators of complement activation gene cluster on the long arm of human chromosome 1, band 1q32. The human beta-chain gene which has now been characterized was found to span more than 10 kilobases of DNA. The presence of at least two... (More)

Human complement component C4b-binding protein (C4BP) is composed of seven alpha-chains and one beta-chain. The alpha- and beta-chains are homologous and both contain multiple copies of short consensus repeats (SCR) and in addition carboxyl-terminal non-repeat regions. Each of the alpha-chains contains a binding site for C4b, whereas the beta-chain binds protein S, a vitamin K-dependent protein involved in the regulation of blood coagulation. The alpha- and beta-chain genes are closely linked in the regulators of complement activation gene cluster on the long arm of human chromosome 1, band 1q32. The human beta-chain gene which has now been characterized was found to span more than 10 kilobases of DNA. The presence of at least two different beta-chain gene transcripts was suggested by the isolation of two new cDNA clones which contained different sequences in their extended 5'-untranslated regions. Northern blot analysis demonstrated that the two clones represented distinct beta-chain mRNAs with different 5' end sequences. One class of beta-chain mRNA (denoted A19) was found to be encoded by six exons and primer extension, and S1 nuclease protection assays revealed multiple closely spaced transcription start sites for this mRNA class. Its 5'-untranslated region and signal peptide was encoded by the first exon. The second class of mRNA (denoted A12) had a different transcription start site and its 5'-untranslated region was derived from at least three exons out of which the last one was formed by utilization of an acceptor splice site within the first A19 exon. Exons encoding the mature beta-chain and the 3'-untranslated region were common to both classes of mRNA. The beta-chain contains three SCRs, out of which the first and second are encoded by individual exons, whereas two exons encode the third SCR. The exon encoding the carboxyl-terminal part of the third SCR also encodes 14 amino acids of the non-repeat region. The last exon encodes the remaining 46 carboxyl-terminal amino acids and the entire 3'-untranslated region. The elucidation of the organization of the beta-chain gene provides insight into the sophisticated molecular structure of C4BP and a basis for future structural and functional studies.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Amino Acid Sequence, Animals, Base Sequence, Carrier Proteins/genetics, Complement C4b/metabolism, Complement Inactivator Proteins, DNA, Exons, Glycoproteins, Humans, Mice, Molecular Sequence Data, RNA, Messenger/genetics, Transcription, Genetic
in
The Journal of biological chemistry
volume
268
issue
20
pages
23 - 15017
publisher
American Society for Biochemistry and Molecular Biology
external identifiers
  • scopus:0027236392
  • pmid:8325877
ISSN
0021-9258
DOI
10.1016/S0021-9258(18)82432-2
language
English
LU publication?
yes
id
57cba363-40ff-4bee-964a-042db7b168fa
date added to LUP
2022-08-29 10:32:51
date last changed
2024-01-03 15:55:54
@article{57cba363-40ff-4bee-964a-042db7b168fa,
  abstract     = {{<p>Human complement component C4b-binding protein (C4BP) is composed of seven alpha-chains and one beta-chain. The alpha- and beta-chains are homologous and both contain multiple copies of short consensus repeats (SCR) and in addition carboxyl-terminal non-repeat regions. Each of the alpha-chains contains a binding site for C4b, whereas the beta-chain binds protein S, a vitamin K-dependent protein involved in the regulation of blood coagulation. The alpha- and beta-chain genes are closely linked in the regulators of complement activation gene cluster on the long arm of human chromosome 1, band 1q32. The human beta-chain gene which has now been characterized was found to span more than 10 kilobases of DNA. The presence of at least two different beta-chain gene transcripts was suggested by the isolation of two new cDNA clones which contained different sequences in their extended 5'-untranslated regions. Northern blot analysis demonstrated that the two clones represented distinct beta-chain mRNAs with different 5' end sequences. One class of beta-chain mRNA (denoted A19) was found to be encoded by six exons and primer extension, and S1 nuclease protection assays revealed multiple closely spaced transcription start sites for this mRNA class. Its 5'-untranslated region and signal peptide was encoded by the first exon. The second class of mRNA (denoted A12) had a different transcription start site and its 5'-untranslated region was derived from at least three exons out of which the last one was formed by utilization of an acceptor splice site within the first A19 exon. Exons encoding the mature beta-chain and the 3'-untranslated region were common to both classes of mRNA. The beta-chain contains three SCRs, out of which the first and second are encoded by individual exons, whereas two exons encode the third SCR. The exon encoding the carboxyl-terminal part of the third SCR also encodes 14 amino acids of the non-repeat region. The last exon encodes the remaining 46 carboxyl-terminal amino acids and the entire 3'-untranslated region. The elucidation of the organization of the beta-chain gene provides insight into the sophisticated molecular structure of C4BP and a basis for future structural and functional studies.</p>}},
  author       = {{Hillarp, A and Pardo-Manuel, F and Ruiz, R R and Rodriguez de Cordoba, S and Dahlbäck, B}},
  issn         = {{0021-9258}},
  keywords     = {{Amino Acid Sequence; Animals; Base Sequence; Carrier Proteins/genetics; Complement C4b/metabolism; Complement Inactivator Proteins; DNA; Exons; Glycoproteins; Humans; Mice; Molecular Sequence Data; RNA, Messenger/genetics; Transcription, Genetic}},
  language     = {{eng}},
  month        = {{07}},
  number       = {{20}},
  pages        = {{23--15017}},
  publisher    = {{American Society for Biochemistry and Molecular Biology}},
  series       = {{The Journal of biological chemistry}},
  title        = {{The human C4b-binding protein beta-chain gene}},
  url          = {{http://dx.doi.org/10.1016/S0021-9258(18)82432-2}},
  doi          = {{10.1016/S0021-9258(18)82432-2}},
  volume       = {{268}},
  year         = {{1993}},
}