Establishment of hybridoma cell line secreting specific monoclonal antibodies against turnip mosaic virus and analysis of properties of the McAb

Monoclonal antibodies (McAb) of hybridomas derived from the fusing of the mouse splenocytes immunized by TuMV with BALB/c mouse myeloma cells (SP2/0-Ag14). Five kinds of hybridoma cell line were produced by indirect-ELISA screening and cloning three times with limiting dilution. Four kinds of hybridoma produced antibodies respectively reactive to TuMV C1, C3, C4 and C5. One kind was reactive to all five strains of TuMV. In indirect-ELISA and sandwich-ELISA tests, TuMV specific monoclonal antibodies did not react with CaMV, CMV, TMV, PVX, and PVY. Antibody titers of ascitic fluids were about 1:256,000 to 2,048,000 in indirect-ELISA. The biological, physical, and chemical properties of the hybridoma cell lines and McAb were identified. The identification of TuMV strains, the specificity and stability of McAb, the coat proteins, and the antigenic site of TuMV were discussed and analyzed with SDS-PAGE and western-blotting.

Construction of hybridomas secreting monoclonal antibody against sweet potato feathery mottle virus and use of antibody for detection of SPFMV

Two hybridomas stably secreting monoclonal antibodies (McAb) against sweet potato feathery mottle virus (SPFMV) were constructed by fusing mouse myeloma (Sp2/0-Ag14) with mouse splenocytes immunized with SPFMV-LF. The McAb secreted by the two hybridomas specifically reacted with both SPFMV-LF (China strain) and SPFMV-RC (American strain) in dot-blot-ELISA. A large amount of McAb was produced with BALB/c mice. The titer of hybridoma cultured supernatant was 1:256, and that of the ascitic fluids was 1:1 x 10(4); and the immunoglobulins of McAb were IgG2a and IgG3 respectively. The detection of SPFMV-infected sweet potato plants with McAb confirmed that the McAb obtained in this test were desirable for large-scale routine surveys of SPFMV. This study on construction of hybridomas and detection of SPFMV using McAb is the first report in the world.

The complete sequence of perlecan, a basement membrane heparan sulfate proteoglycan, reveals extensive similarity with laminin A chain, low density lipoprotein-receptor, and the neural cell adhesion molecule

A heparan sulfate proteoglycan is a component of all basement membranes. This molecule consists of three heparan sulfate side chains linked to a large core protein of approximately 400 kDa. We have isolated seven overlapping murine cDNA clones that encode the entire mRNA sequence of 12.685 kilobases of this molecule. This sequence has a single open reading frame of 3,707 amino acids that encodes for a protein of 396 kDa. Identical or near identical matchups with nine peptide sequences derived from the core protein of the molecule isolated from the Engelbreth-Holm-Swarm tumor were found with the deduced sequence. Sequence analysis and data base comparison of the deduced sequence show the protein to consist of five different domains, most of which contain internal repeats. Domain I contains a start methionine followed by a typical signal transfer sequence and a unique segment of 172 amino acids that contains the three probable sites of heparan sulfate attachment, SGD. Domain II contains four cysteine- and acidic amino acid-rich repeats that are very similar to those found in the LDL receptor and proteins such as GP330. Domain III consists of cysteine-rich and globular regions, both of which show similarity to those in the short arm of the laminin A chain. Domain IV contains 14 repeats of the immunoglobulin superfamily that are most highly similar to the immunoglobulin-like repeats in the neural cell adhesion molecule. Domain V contains three repeats with similarity to the laminin A chain G domain that are separated by epidermal growth factor-like regions not found in the laminin A chain. As the primary structural data agree with the appearance of the molecule in the electron microscope as a series of globules separated by rods, or "beads on a string," we have adopted the name perlecan for this molecule. The variety of domains in perlecan suggest multiple interactions with other molecules.

Biotinylation of denatured double-stranded DNA after transamination of cytidines: molecular biology applications

Transamination at 100 degrees C of cytosines in denatured double-strand DNA is a rapid and reliable method to obtain DNA molecules containing N4-aminoethylcytosine (4aeC), which can be quantitatively conjugated to biotinyl-N-hydroxysuccinimide ester (BHS) at 37 degrees C, yielding chemically labelled probes for molecular hybridization. The adopted transamination reaction temperature allows for a ten-fold reduction of the time required for labelling at 42 degrees C, and probes obtained by this procedure are equally effective for general use in molecular biology. Dot-blots with 1-5 pg of target lambda DNA were detected by streptavidin-acid phosphatase complex after hybridization with its homologous sequences. Chemically biotinylated mouse satellite DNA has been used in combination with avidin-horseradish peroxidase to detect metaphase and interphase centromeres via in situ hybridization. Moreover probes labelled with differentially spaced linker arms were prepared by this method.

Biotinylation of double stranded DNA after transamination

The bisulfite catalyzed transamination of cytidine and cytosine has been reported to be single strand specific, but local thermal instabilities of the DNA double helix, coupled with the extreme sensitivity of the Biotin-Avidin revelation methods, allows the random labelling of cytosines in d.s. DNA to detectable levels for those purposes where the overall label can be very low. We have evaluated the use of this reaction to prepare double stranded DNA molecules containing N4-aminoethyl-cytosine (4-aeC). After this step 4-aeC residues can be conjugated to biotinyl-n-hydroxysuccinimide ester yielding biotinylated DNA. This reaction allows the massive production of biotinylated probes. Labelled DNA can serve as molecular weight marker and positive control in Southern-blots. Moreover it can be useful in the study of DNA-protein interaction and in the isolation of d.s. DNA-binding proteins through chromatographic procedures.