Complete cDNA sequence of human complement C1s and close physical linkage of the homologous genes C1s and C1r

Journal Article · Tue Dec 29 04:00:00 EST 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00400a004· OSTI ID:5410265

Tosi, M; Duponchel, C; Meo, T; Julier, C

Overlapping molecular clones encoding the complement subcomponent C1s were isolated from a human liver cDNA library. The nucleotide sequence reconstructed from these clones spans about 85% of the length of the liver C1s messenger RNAs, which occur in three distinct size classes around 3 kilobases in length. Comparisons with the sequence of C1r, the other enzymatic subcomponent of C1, reveal 40% amino acid identity and conservation of all the cysteine residues. Beside the serine protease domain, the following sequence motifs, previously described in C1r, were also found in C1s: (a) two repeats of the type found in the Ba fragment of complement factor B and in several other complement but also noncomplement proteins, (b) a cysteine-rich segment homologous to the repeats of epidermal growth factor precursor, and (c) a duplicated segment found only in C1r and C1s. Differences in each of these structural motifs provide significant clues for the interpretation of the functional divergence of these interacting serine protease zymogens. Hybridizations of C1r and C1s probes to restriction endonuclease fragments of genomic DNA demonstrate close physical linkage of the corresponding genes. The implications of this finding are discussed with respect to the evolution of C1r and C1s after their origin by tandem gene duplication and to the previously observed combined hereditary deficiencies of Clr and Cls.

• Research Organization: Institut Pasteur, Paris (France)
• OSTI ID: 5410265
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:26; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

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59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMALS
AUTORADIOGRAPHY
BIOLOGICAL EVOLUTION
BODY
COMPLEMENT
DIGESTIVE SYSTEM
DISEASES
DNA
DNA SEQUENCING
ELECTROPHORESIS
GENES
GLANDS
HEREDITARY DISEASES
HYBRIDIZATION
LIVER
MAMMALS
MAN
MESSENGER-RNA
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PRIMATES
RECOMBINANT DNA
RNA
STRUCTURAL CHEMICAL ANALYSIS
VERTEBRATES