PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 4100685

C1r, subunit of the first complement component: purification, properties, and assay based on its linking role.

M M De Bracco·R M Stroud
View original source ↗Export metadata ↓

Abstract

A method to obtain C1r, a subunit of the first complement component, in a highly purified state has been described for the first time. The stepwise method starts with a neutral euglobulin precipitation, after diethylaminoethyl- and carboxymethyl-cellulose chromatography and a final preparative polyacrylamide electrophoresis step. Such C1r preparations are devoid of C1q and C1s activities and show only one protein band on analytic polyacrylamide electrophoresis. Rabbits injected with this preparation produced antisera showing only one precipitation band. The stability of C1r activity was determined under different conditions, and C1r was found to be labile at 37 degrees C, pH 7-8 and low ionic strength. The electrophoretic mobility of purified C1r is that of a beta-globulin on disc acrylamide electrophoresis and on agarose electrophoresis at pH 8.6. Its molecular weight as estimated by sephadex chromatography is 168,100.A sensitive hemolytic assay based on the property of C1r to link C1s to C1q and thereby to generate macromolecular C[unk]1 is described. The number of C[unk]1 molecules generated is stoichiometrically related to the concentration of C1r for a fixed C1q and C1s concentration provided that the titration is carried out below the plateau zone. Macromolecular C1 can be separated from free C1s as the former is cell bound. This method of purification and assay should allow the development of monospecific antisera and further chemical study of C1r.

Explore related subjects

Beta-GlobulinsChromatography, DEAE-CelluloseChromatography, GelComplement System ProteinsElectrophoresis, DiscHemolysisHydrogen-Ion ConcentrationImmunodiffusionImmunoelectrophoresisKineticsMethodsSerum Albumin, Radio-IodinatedJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

M M De Bracco, R M Stroud. 1971. C1r, subunit of the first complement component: purification, properties, and assay based on its linking role.. https://doi.org/10.1172/jci106555

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2005

C/EBPdelta and C/EBPgamma bind the CCAAT-box in the human beta-globin promoter and modulate the activity of the CACC-box binding protein, EKLF.

Developmental- and tissue-specific expression of globin genes is mediated by a few key elements within the proximal promoter of each gene. DNA-binding assays previously identified NF-Y, GATA-1, C/EBPbeta and C/EBPgamma as candidate regulators of beta-globin transcription via the CCAAT-box, a promoter element situated between CACC- and TATA-boxes. We have identified C/EBPdelta as an additional beta-globin CCAAT-box binding protein. In reporter assays, we show that C/EBPdelta can co-operate with EKLF, a CACC-box binding protein, to activate the beta-globin promoter, whereas C/EBPgamma inhibits the transcriptional activity of EKLF in this assay.

Beta-Globulins↗
PubMed2005

The spectrum of beta-globin gene mutations in children with beta-thalassaemia major from Kota Kinabalu, Sabah, Malaysia.

INTRODUCTION: Beta-thalassaemia major is one of the commonest genetic disorders in South East Asia. The strategy for the community control of beta-thalassaemia major requires the characterisation of the spectrum of beta-globin gene mutations in any multi-ethnic population. There is only a single report of mutation analyses of the beta-globin gene in an isolated Kadazandusun community in Kota Belud, Sabah, Malaysia, which showed the presence of a common 45 kb deletion. METHODS: To confirm the observation that this large deletion is the commonest beta-globin gene mutation among the Kadazandusun and other indigenous populations in Sabah, Malaysia, we performed polymerase chain reaction (PCR) analysis of the beta-globin gene in ten children with beta-thalassaemia major attending the Thalassaemia Centre, Queen Elizabeth Hospital, the major paediatric referral centre in Kota Kinabalu, Sabah. RESULTS: The 45 kb deletion was confirmed to be the commonest mutation found in the Kadazandusun, Bajau and Murut populations, whereby it was detected in 19 out of the 20 (95 percent) alleles analysed. The other mutation was due to an IVS-1 position 1 G > T mutation. CONCLUSION: This finding confirmed the deletion in the homozygous state was associated with a severe phenotype. The reason for the predominance of this mutation in Kota Kinabalu is most likely to be due to founder effects and possibly intermarriages between the various ethnic groups. Prenatal diagnosis using PCR for this common mutation is feasible in this community. Medical workers and scientists at molecular diagnostic centres serving large South East Asian populations should incorporate a diagnostic strategy for this deletion in the appropriate population. Future studies on these indigenous ethnic groups in other areas and other groups in Sabah are required.

Beta-Globulins↗
PubMed2005

Clinical phenotypes and molecular diagnosis in a hitherto interaction of Hb E/beta thalassemia syndrome (beta(E)/beta(-31), (A -->G)).

Molecular identification of affected alleles in the index family with rare mutation(s) and/or interaction(s) is an important prerequisite toward a proper genetic counseling. In Thailand, where more than 30% of the populations are heterozygotes for either alpha or beta thalassemia mutation(s). More than 60 different thalassemia syndromes resulting from the interactions of these heterogeneous alleles have been observed. The majority of patients in the hospital based-study are compound heterozygotes for beta thalassemia alleles and another hemoglobinopathy namely Hb E, highly prevalent in Thailand, gave rise to Hb E/beta thalassemia syndrome. The phenotypes of these syndromes vary from asymptomatic individual to a very severe phenotype mimic that of beta thalassemia major. In this report, we describe a three-year-old Thai girl presenting with mild hypochromic microcytic anemia since birth. She was born prematurely and developed anemia within the first week of life. The cause of anemia was suspected to result from prematurity and low intrauterine iron storage, however hypochromic anemia did not resolve after a three-month of iron supplement therapy. Subsequent studies indicated that the patient had Hb E/beta thalassemia disease and the molecular study revealed that the patient was a compound heterozygote for Hb E and a rare beta thalassemia mutation (beta(-31), A --> G). This hitherto genotype results in a relatively mild clinical symptom since the patient's baseline Hb values were around 9-10 g/dL with normal weight and height development during the follow-up period.

Beta-Globulins↗