A血型单克隆抗体的抗原结合部位结构多样性研究

应用杂交瘤技术,以Ａ型红细胞,Ａ１血型物质ＭＳＭ（Ａ１）和Ａ－ＲＢＣ＋ＭＳＭ（Ａ１）为免疫原,制备了一组抗人Ａ血型单克隆抗体：Ａ１２１８,Ｂ５７,ＤＥ９２３－Ｇ８,Ｄ２８６－Ｅ１２经Ｔａｋａｔｓｙ微量血细胞凝集试验证明：这组单抗仅能凝集Ａ１,Ａ２及ＡＢ型红细胞,不能凝集Ｂ,Ｏ型红细胞．采用ＥＬＩＳＡ定量抑制试验法,精确测定了它们抗原结合部位的结构,互补于Ａ活性寡糖。Ａ１２１８互补于具有双岩藻糖结构的Ａ活性五糖（Ａ－Ｐｅｎｔａ）;Ｂ５７,ＤＥ９２３－Ｇ８互补于具有单岩藻糖结构的Ａ活性六糖（Ａ－Ｈｅｘａ）;而Ｄ２８６－Ｅ１２则互补于具有单岩藻糖的Ａ活性四糖（Ａ－Ｔｅｔｒａ）．结果表明：血凝特异性相同的抗Ａ单抗,其抗原结合部位的结构可呈现多样性。即Ａ活性寡糖的糖基组成数目和含有岩藻糖数目均可不相同,各种抑制剂对不同单抗的抑制作用强弱也不相同。     

Complementary idiotypy in the regulation of the immune response.

A new concept is presented for the interactions of two complementary antibodies in the immune response. These antibodies bind to each other by means of their variable sequence determinants and therefore are designated as complementary idiotypes. Under certain conditions, both complementary idiotypes are produced by the same animal at the same time. An idiotype can drastically affect the expression of the complementary idiotype in the animal, inducing a peripheral quench effect of antibody-binding activity and a central effect on the immunocompetent cell, which produces the complementary idiotype. It is proposed that complementary idiotypes might be induced during every immune response, thus playing an essential role in the regulation of the immune response.     

Discrete and heterogeneous high molecular weight RNAs complementary to a long dispersed repeat family (a possible transposon) of human DNA

Approximately 1% of heterogeneous nuclear RNA and approximately 0.035% of cytoplasmic RNA from a cultured line of human lymphoblastoid cells is complementary to a long dispersed repetitious sequence that comprises at least 6% of human DNA. The complementary nuclear RNA is both heterogeneously and discretely sized and is present in both poly(A)-terminated and non-poly(A)-terminated molecules. The complementary cytoplasmic RNA is mainly in discretely sized molecules ranging in size from approximately 600 to 8200 bases, some of which are most abundantly represented in poly(A)-terminated molecules, whereas others are most abundantly represented in non-poly(A)-terminated molecules. Few, if any, of the complementary cytoplasmic RNAs can be found associated with polyribosomes. The dispersed repeat sequence exhibits substantial restriction enzyme fragment length polymorphisms in human DNA and is also present in mouse DNA, although some regions of the human repeat appear to be more abundantly represented in mouse DNA than are other regions.     

Activation of Balbiani ring genes inChironomus tentans after a pilocarpine-induced depletion of the secretory products from the salivary gland lumen

We have constructed recombinant plasmid libraries containing complementary DNA (cDNA) inserts made to poly(A)⁺ RNA isolated from two stages of Dictyostelium development. The procedure utilized for the cloning allows the excision of the cDNA inserts free of vehicle sequences. The two libraries were screened for inserts complementary to moderately abundant and abundant poly(A)⁺ RNA whose genes are differentially modulated during Dictyostelium development. Several of these plasmids were then further examined by hybridization techniques to determine the reiteration frequencies of their genes, the relative rate of complementary RNA synthesis during development, and the relative accumulation and disappearance of complementary RNA during the Dictyostelium life cycle. RNA complementary to two sequences was found to accumulate from approximately one molecule per cell during vegetative growth to several hundred molecules during preaggregation.     

The inhibitory effect of oligodeoxynucleotides complementary to different fragments of tRNA structure on the enzymatic binding of Phe-tRNA to poly-U-programmed eukaryotic ribosomes

The effect of several oligodeoxynucleotides complementary to the fragments of yellow lupin tRNA(Phe) was tested in the aminoacylation of tRNA(Phe) and in the binding of Phe-tRNA(Phe) to poly-U-programmed eukaryotic ribosomes. Oligonucleotides tested in the aminoacylation test did not give any inhibition. Monomers and dimers did not have any significant influence on the binding assay, either. A different percentage of inhibition of the binding of Phe-tRNA to ribosomes has been observed for oligonucleotides. Heptamer complementary to the anticodon loop gave 100% inhibition of the binding reaction. However, the oligonucleotides complementary to both the anticodon loop and stem and longer than the heptamer were much less effective inhibitors. A high inhibitory effect was also observed for trimers and for the decamer complementary to the D-loop and CCA-end.     

Molecular cloning and characterisation of cDNAs complementary to mRNAs from wounded potato (Solanum tuberosum) tuber tissue

Five cDNA clones complementary to mRNAs representing different abundances and responses to wounding have been isolated from a library of Sau 3A fragments in the bacteriophage M13 mp8. These were characterised by hybrid-release translation and hybridisation to RNA blots. The levels of RNA complementary to two of the clones show a marked increase during the 24h after wounding, one shows a small increase and two show no appreciable changes except that caused by a general increase in the total amount of polyadenylated RNA per microgram of total RNA which increases 2.5-fold during the same period. The would-induced RNAs are not induced in diluted suspension-culture cells, but RNA complementary to each clone is present in varying levels in stems, leaves and roots of intact potato plants.Abbreviations cDNA complementary DNA - poly(A) polyadenosine - poly(A)⁺ RNA polyadenylated RNA - poly(U) polyuridine     

Complementary DNA sequence of a human cytoplasmic actin. Interspecies divergence of 3' non-coding regions

We have isolated and sequenced a cloned complementary DNA insert complementary to the messenger RNA of a cytoplasmic actin expressed in human epidermal cells. This provides the first cytoplasmic actin complementary DNA sequence for a vertebrate organism. The actin amino acid sequence predicted from this complementary DNA is identical to that of a bovine cytoplasmic actin and shows 98 and 85% homology with a Dictyostelium and a yeast actin, respectively. The complementary DNA sequence indicates that the 3' end of the mRNA contains an unusually long (greater than 400 nucleotides) 3' non-translated region. A comparison of this 3' non-coding region with those of recently determined actin complementary DNA sequences from other species reveals little or no homology among these sequences. Thus, these results indicate that although the actin amino acid sequences are extremely conserved, the non-coding regions of the mRNAs diverge rapidly.     

Expression Activity of CLCuV Bidirectional Promoter in Agrobacterium tumefaciens

Cotton leaf curl virus (CLCuV) belongs to the subgroup Ⅲ of geminiviruses with single strand DNA genome. Study demonstrated that the bidirectional promoter of CLCuV had activity in Agrobacterium tumefaciens (Smith et Townsend) Conn. This is the first report for the activity of the bidirectional promoter of geminivirus in A. tumefaciens . Results showed that the activity of the complementary sense promoter was stronger than that of virion sense promoter, and was detected 2-fold higher than that of CaMV 35S promoter in A. tumefaciens . Moreover, the promoter 5′ deletion analysis indicated that the mean GUS activity driven by a 287 nucleotides complementary sense promoter fragment (from -287 to the translation initiation site) is 4 times higher than that driven by the whole complementary sense promoter in A. tumefaciens . This result suggested that there might exist negative regulatory elements in this deleted fragment. The function of other cis- elements included in CLCuV complementary sense promoter was also discussed in this paper.     

Direct detection of usual and atypical alleles on the human aldehyde dehydrogenase-2 (ALDH2) locus.

A method for determining human mitochondrial aldehyde dehydrogenase (ALDH2) genotypes was developed. Two 21-base synthetic oligonucleotides, one complementary to the usual ALDH2(1) gene and the other complementary to the atypical ALDH2(2) gene, were used as specific probes for in-gel hybridization analysis of human genomic DNA from either peripheral blood cells or livers. Under appropriate hybridization conditions, these two probes can hybridize to their specific complementary alleles and thus allow the genotyping of the ALDH2 locus.     

Effect of mic gene structure on repressor activity in the OmpA system

It has been previously established that micRNA (mRNA-interfering complementary RNA) complementary to an individual mRNA specifically represses the expression of the target mRNA. We have constructed several plasmids which produce micRNAs which are complementary to different regions of the ompA mRNA. The repressor activity of these different micRNAs has been compared to determine the role of mic gene structure in effective micRNA function. The results indicate that micRNAs complementary to regions of the ompA mRNA likely to encounter ribosomes have the highest repressor activities. A clear effect of mic gene dosage was also observed. This was demonstrated using both identical and different mic(ompA) genes.     

Construction and characterization of a plasmid containing complementary DNA to mRNA encoding the N-terminal amino acid sequence of the rat glutathione transferase Ya subunit.

Free polyribosomal poly(A)-containing RNA isolated from normal rat liver was used to prepare a complementary DNA plasmid library in the Pst1 site of the plasmid pAT153 . A plasmid pGSTr155 complementary to mRNA coding for a glutathione transferase Ya subunit was selected by differential hybridization in situ and preliminary characterization was performed by hybrid-selected mRNA translation, immunoprecipitation and polyacrylamide-gel electrophoresis of the product synthesized in vitro. The nucleotide sequence of the complementary DNA contained within pGSTr155 was determined and shown to contain a single open reading frame corresponding to the first 129 amino acids of the N-terminus of the Ya subunit and a further 63 nucleotides upstream of the initiating methionine codon.     

Association of star-shaped poly(D,L-lactide)s containing nucleobase multiple hydrogen bonding

A new family of associating polymers based on four-arm, star-shaped poly(D,L-lactide) (PDLLA) containing peripheral complementary hydrogen-bonding sites is described. Hydroxy-terminated, four-arm, star-shaped PDLLAs of controlled molar mass were functionalized with complementary DNA base pairs, adenine (A) and thymine (T), to obtain PDLLA-A and PDLLA-T, respectively. 1H NMR spectroscopy confirmed quantitative functionalization and the subsequent formation of PDLLA-A and PDLLA-T hydrogen-bonded complexes. Job's analysis revealed a 1:1 optimal stoichiometry for the hydrogen-bonded complexes, and the association constant (Ka) that was determined using the 1H NMR-based Benesi-Hildebrand treatment was 84 M(-1) for the low molar mass complementary polymers. Furthermore, the PDLLA-based hydrogen-bonded complexes exhibited higher solution viscosities compared to the corresponding non-hydrogen-bonded precursors, which further confirmed strong complementary multiple-hydrogen-bonding associations between the star-shaped polymers with terminal adenine and thymine groups. Moreover, variable-temperature 1H NMR studies demonstrated the thermoreversibility of the hydrogen-bonded PDLLA-based complexes in solution.     

Affinity enhancement of complementary peptide recognition.

A peptide hydropathically complementary to Big Endothelin [Big ET] residues 16-29 has been synthesized in a multimeric form starting from an octadentate polylysine core, essentially in a way similar to the procedure used for the production of multiple antigenic peptides [MAP's]. Interaction between the multimeric complementary peptide [8 delta ET] and the Big ET fragment 16-32 containing the target complementary region, also synthesized in a multimeric form [8ET], was evaluated by analytical high performance affinity chromatography and solid phase binding assays. While the binding interaction between the monomerics peptide pair was in the micromolar range, the recognition between the corresponding multimeric form was characterized by enhanced binding affinity of at least two orders of magnitude. In solution, complex formation between multimeric complementary peptide and target Big ET sequence in the monomeric and multimeric form was accompanied by precipitation at concentrations higher than 0.5 mg/mL and 0.1 mg/mL, respectively. Polyclonal antibodies raised against the multimeric target sequence recognized multimeric and monomeric ET target sequences with binding affinities similar to binding affinities exhibited by the multimeric complementary peptide. Multimerization of hydropathically complementary peptides could provide an improved opportunity to measure and thus probe quantitative binding properties of complementary peptides.     

Isolation and characterization of cDNA complementary to transient maternal poly(A)+ RNA from the Drosophila oocyte.

cDNA complementary to total oocyte poly(A)+ RNA from Drosophila melanogaster was enriched for sequences complementary to transient maternal sequences; that is, those sequences which disappear from the oocyte during subsequent. A seven- to ten-fold enrichment factor was obtained, from 5.3% to about 50% of the total cDNA. Kinetic analysis of this enriched fraction indicates that the transient maternal sequences include 44 +/- 14 different sequences.     

G1 arrest and the division/conjugation decision in Tetrahymena.

The transformation from the asexual proliferative stage of Tetrahymena to the sexual stage, during which cells of complementary mating types pair and nuclear fertilization occurs, provides an opportunity to study the relationship between the division cycle and differentiation. Conjugation is induced in cells starved for at least 2 hr by mixing complementary mating types. To determine the effect of starvation on the cell cycle, dividing cells were selected from a log growth culture and stepped down to non-nutrient conditions. The G₁ stage is operationally divisible into two sectors, A and B. In the A stage, cells arrest in nutrient-free medium. In the B stage, they proceed through the division cycle. Arrested G₁A cells may conjugate directly when challenged with similar cells of a complementary mating type. It is thereby demonstrated that Tetrahymena cells in G₁A can be directed to divide (nutrient conditions) or can be directed to differentiate (non-nutrient conditions plus complementary mating type) without an intervening division cycle. This rules out a requirement for reprogramming via chromosomal replication or cell division and suggests that G₁A is a stage during which the division/differentiation decision is made in direct response to ambient conditions.     

Putative implication of 3′-terminal segment of 18S rRNA in translation initiation of uncapped mRNAs in plants

A putative implication 3′-terminal 18S rRNA segment in the cap-independent initiation of translation on plant ribosomes was studied. It was shown that 3′-terminal segment (nucleotides 1777–1811) of 18S rRNA including the last hairpin 45 was accessible for complementary interactions within 40S ribosomal subunits. Oligonucleotides complementary to this segment of rRNA, when added to wheat germ cell-free protein synthesizing system, specifically inhibited translation of uncapped reporter mRNA encoding β-glucuronidase. In the 5′-untranslated region (UTR), the reporter mRNA contained a leader sequence of potato virus Y (PVY) genomic RNA with fragments complementary to the region 1777–1811. A sequence corresponding to nucleotides 291–316 of PVY, which was complementary to most of the 3′-terminal 18S rRNA segment 1777–1808, was shown to enhance translational efficiency of the reporter mRNAs when placed into 5′-UTR. The obtained results suggest that complementary interactions between 5′-UTR of mRNA and 3′-terminal segment of 18S rRNA can take place during cap-independent translation initiation.