Visualization and analysis of unfolded nucleosomes associated with transcribing chromatin

We have characterized the structure of transcriptionally active nucleosome subunits using electron spectroscopic imaging. Individual nucleosomes were analyzed in terms of total mass, DNA and protein content, while the ensemble of images of active nucleosomes was used to calculate a three-dimensional reconstruction. Transcriptionally active nucleosomes were separated from inactive nucleosomes by mercury-affinity chromatography thus making it possible to compare their structures. The chromatographic results combined with electron spectroscopic imaging confirm that active nucleosomes unfold to form extended U-shaped particles. Phosphorus mapping indicated that the nucleosomal DNA also underwent a conformational change consistent with particle unfolding. The three-dimensional structure of the Hg-affinity purified nucleosomes determined using quaternion-assisted angular reconstitution methods unites and resolves the different electron microscopic views of the particle and is concordant with a sulphydryl-exposing disruption of the H3-H4 tetramer.

Single-step electrotransfer of reverse-stained proteins from sodium dodecyl sulfate-polyacrylamide gel onto reversed-phase minicartridge and subsequent desalting and elution with a conventional high-performance liquid chromatography gradient system for analysis

Isolation of proteins from polyacrylamide electrophoresis gels by a novel combination of techniques is described. A given protein band from a reverse stained (imidazol-sodium dodecyl sulfate--zinc salts) gel can be directly electrotransferred onto a reversed-phase chromatographic support, packed in a self-made minicartridge (2 mm in thickness, 8 mm in internal diameter, made of inert polymeric materials). The minicartridge is then connected to a high-performance liquid chromatography system and the electrotransferred protein eluted by applying an acetonitrile gradient. Proteins elute in a small volume ( < 700 microL) of high-purity volatile solvents (water, trifluoroacetic acid, acetonitrile) and are free of contaminants (gel contaminants, salts, etc). Electrotransferred proteins were efficiently retained, e.g., up to 90% for radioiodinated alpha-lactalbumin, by the octadecyl matrix, and their recovery on elution from the minicartridge was in the range typical for this type of chromatographic support, e.g., 73% for alpha-lactalbumin. The technique was successfully applied to a variety of proteins in the molecular mass range 6-68 kDa, and with amounts between 50 and 2000 pmol. The good mechanical and chemical stability of the developed minicartridges, during electrotransfer and chromatography, allowed their repeated use. This new technique permitted a single-step separation of two proteins unresolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis due to their different elution from the reversed-phase support. The isolated proteins were amenable to analysis by N-terminal sequencing, enzymic digestion and mass spectrometry of their proteolytic fragments. Chromatographic elution of proteins from the reversed-phase mini-cartridge was apparently independent of the specific loading mode employed, i.e., loading by conventional loop injection or by electrotransfer.

Direct blotting, sequencing and immunodetection of proteins after five-minute staining of SDS and SDS-treated IEF gels with Nile red

The non-covalent dye Nile red allows the fast and simple fluorescent staining of protein bands in sodium dodecyl sulfate (SDS)-polyacrylamide gels. This procedure has been extended to polyacrylamide isoelectric focusing gels that do not contain SDS. Unlike the current methods using Coomassie blue or silver for gel staining, Nile red staining does not preclude the direct electroblotting of protein bands onto polyvinylidene difluoride membranes, and the transferred proteins can be used directly for immunoblotting analysis and for N-terminal microsequencing.

Recovery of transcriptionally active chromatin restriction fragments by binding to organomercurial-agarose magnetic beads. A rapid and sensitive method for monitoring changes in higher order chromatin structure during gene activation and repression

The unfolding of nucleosomes along transcriptionally active DNA sequences uncovers previously shielded cysteinyl-thiol groups of histone H3 molecules located at the center of the nucleosome core. This change in conformation and SH reactivity of nucleosomes along transcribed DNA sequences makes it possible to separate active from inactive nucleosomes by mercury affinity chromatography. The binding of thiol-reactive nucleosomes to an organomercurial-agarose column has been shown previously to reflect, with accuracy, both the timing and extent of transcription of the associated DNA sequences (Chen, T. A., and Allfrey, V. G. (1987) Proc. Natl. Acad. Sci. U. S. A. 84, 5252-5256). Here, we extend this experimental approach to the analysis of higher order chromatin structures. Large chromatin fragments released by treating isolated nuclei with restriction endonucleases are fractionated on mercurated agarose magnetic beads that capture nucleosomes with accessible histone H3 thiols, but do not react with the hidden H3 thiols of the compactly beaded nucleosomes of inactive genes. The SH-reactive domains of c-myc and other genes are rapidly separated from the non-SH-reactive restriction fragments by the magnetic bead technique. The new method also overcomes a major limitation of mercurated agarose column chromatography, which is not suitable for studies of higher order chromatin structure because large chromatin fragments occlude the mercury column; occlusion is not a problem in magnetic separations using suspended mercurated agarose beads. Here, we describe the synthesis of mercurated agarose magnetic beads with high capacity for SH groups and test their application to the recovery of chromatin restriction fragments of c-myc and the growth arrest gene gas1.

Identification of arginyl residues involved in the binding of ferredoxin-NADP+ reductase from Anabaena sp. PCC 7119 to its substrates

Ferredoxin-NADP+ reductase from the cyanobacterium Anabaena sp. PCC 7119 was chemically modified by the alpha-dicarbonyl reagent phenylglyoxal. The studies of the inactivation by this compound, which is specific for arginyl residues, of both the diaphorase and NADPH-cytochrome c reductase activities, characteristic of the enzyme, are indicative of the involvement of at least one group of this kind in the binding site of NADP+ and a second one implicated in the interaction with ferredoxin. After specific cleavage of a FNR sample incubated with [7-14C]phenylglyoxal, two major labeled peptides were identified. The peptide which exhibited the higher degree of modification corresponded to residues 208-242. It contained four arginine residues but only two of them were the target of the modification: Arg224 and Arg233. Protection studies with protein substrates and sequence comparison with other reductases allow us to propose that these residues in Anabaena sp. PCC 7119 FNR must be involved in the interaction with the pyridine nucleotide. The second peptide corresponds to residues 75-103 and although it contains three arginine residues, Arg77 is the only one that exhibits the modification. This residue seems to be a key one in the interaction of this reductase with ferredoxin.

Identification of the three major coeliac immunoreactive proteins and one alpha-amylase inhibitor from oat endosperm

Six chloroform/methanol-soluble proteins from oat endosperm (Avena sativa) have been isolated and characterized by a purification procedure based on extraction with volatile solvents, followed by reversed-phase high performance liquid chromatography. Three of these proteins, with an assessed molecular weight of 25,000, 27,000 and 32,000 Da, respectively, have been identified by immunoblotting using coeliac sera, as the major coeliac serum IgA-binding components of oat endosperm. The N-terminal amino acid sequence of these proteins indicates that they correspond to alpha 2, gamma 4, and gamma 3 avenins, respectively. We have tentatively named them 'coeliac immunoreactive proteins'. Another chloroform/methanol oat component shows weak alpha-amylase inhibitory activity and exhibits strong homology (60% identity) at the N-terminus with the alpha-amylase inhibitor from ragi (Eleusine coracana).

Knowledge of medication in hospitalized chronic respiratory patients

Object of the study was to assess educative needs in the field of drug therapy among 99 chronic patients with advanced chronic lung disease admitted to the Respiratory Service of the Hospital Sta. Creu i Sant Pau (Barcelona, Spain). The knowledge of the patients about their previous drug treatment, sources of information as well as patients' conception of side-effects, was gathered from medical records and by means of a questionnaire. The majority of patients studied were male (63%), aged over 60 years (average 63 +/- 12), illiterate or with basic education (88%), had a chronic obstructive, pulmonary disease (76%) and with an important degree of chronicity. They had been treated for their condition during a mean of 8.4 years and took an average of 4.6 drugs. 31% Of patients did not answer any question about their medication properly and only 17% gave a correct answer to all the questions. The lower the age and the higher the educational level, the higher the proportion of correct answers to knowledge questions. 35% Of the patients stated not to have been informed about their medication and 55% stated that they had read the patient package inserts.

Isolation and partial characterization of a new ribosome-inactivating protein from Petrocoptis glaucifolia (Lag.) Boiss

Petrocoptis glaucifolia, a paleoendemic member of the Caryophyllaceae from the North of Spain, was found to contain at least five proteins that inhibit protein synthesis in a rabbit reticulocyte lysate. One of them, for which the name petroglaucin is proposed, was purified to apparent electrophoretic homogeneity by chromatography through S-Sepharose Fast Flow, Sephadex G-75 and CM-Sepharose Fast Flow. The apparent Mr of the preparation was 27500. This protein does not contain appreciable glycan chains and displays 45.8% of NH2-terminal amino-acid sequence homology with some ribosome-inactivating proteins from Saponaria officinalis, another member of the Caryophyllaceae. Petroglaucin shows the following functional properties: (i) it strongly inhibits the rabbit-reticulocyte-lysate system and Vicia sativa cell-free extracts, both coded by endogenous messengers, and also inhibits poly(U)-directed polyphenylalanine synthesis by Vicia sativa cell-free extracts and purified rat-liver ribosomes; (ii) it shows much less inhibitory capacity in wheat-germ, Cucumis sativus and rat-liver cell-free systems coded by endogenous messengers; (iii) the inhibitory effects on purified rat-liver ribosomes were irreversible; (vi) it promotes the release of adenine from purified rat-liver ribosomes. The total activity of this translational inhibitor has been found to increase up to 11-fold during its purification, indicating that some regulatory factor that normally blocks the translational inhibitory activity of the ribosome-inactivating protein in crude extracts of the plant is removed during purification.

Lysine residues on ferredoxin-NADP+ reductase from Anabaena sp. PCC 7119 involved in substrate binding

Ferredoxin-NADP+ reductase from Anabaena sp. PCC 7119 is chemically modified by pyridoxal 5'-phosphate. The incorporation of 2 +/- 0.3 mol pyridoxal 5'-phosphate/mol ferredoxin-NADP+ reductase inhibited NADPH-cytochrome c reductase activity by up to 95% while 55% of diaphorase activity still remained. Considerable protection against inactivation was afforded by ferredoxin. Chymotryptic cleavage of the modified enzyme was performed, the peptides were separated by high performance liquid chromatography, and the peptides containing pyridoxamine 5'-phosphate were identified by their fluorescence and by their absorbance at 325 nm. Three major labelled peptides were found. Their sequences were comprised of residues 46-54, 231-235 and 289-295. Lys-53 and -294 were the residues which presented the highest degree of modification and seem to be involved in the ferredoxin binding site of ferredoxin-NADP+ reductase from Anabaena sp. PCC 7119.

Identification of specific carboxyl groups on Anabaena PCC 7119 flavodoxin which are involved in the interaction with ferredoxin-NADP+ reductase

Flavodoxin from the nitrogen-fixing cyanobacteria Anabaena PCC 7119 forms an electron-transfer complex with ferredoxin--NADP+ reductase (FNR) from the same organism. The complex is mainly governed by electrostatic interactions between side-chain amino groups of the reductase and carboxyl residues of flavodoxin. In order to localize the binding site on flavodoxin, chemical modification of its carboxyl groups has been carried out. Treatment of flavodoxin with a water-soluble carbodiimide, N-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), in the presence of a nucleophile, glycine ethyl ester, caused a time-dependent modification of the protein that is responsible for the loss of its ability to participate as electron carrier in the photoreduction of NADP+ by chloroplast membranes, and also in NADPH--cytochrome-c reductase activity, by about 85%. Nevertheless, the ability of flavodoxin to receive electrons from the reducing side of photosystem I was much less affected. The inhibition was enhanced at low pH, suggesting that carboxylic acid groups were the target of chemical modification. Treated flavodoxin failed to form covalent complexes with FNR and the dissociation constant for the non-covalent complex with FNR was fourfold higher. After tryptic digestion of a sample of flavodoxin modified by EDC in the presence of [1-14C]glycine ethyl ester, two major radioactive peptides were isolated. The first protein fragment contained three carboxylic residues (Asp123, Asp126 and Asp129), corresponding to the region where long-chain flavodoxins show an insert compared to short-chain flavodoxins. The second peptide corresponded to a similar region, either in the amino acid sequence or in the three-dimensional structure of the protein and also containing three carboxyl groups (Asp144, Glu145 and Asp146). Four of these carboxyl groups (Asp123, Asp126, Asp144 and Asp146) are highly conserved in all long-chain flavodoxins, suggesting that they could play an essential role in substrate recognition.

The Department of Defense Civilian External Peer Review Program: an interim report

During a 2-year period (December 1987-December 1989), 165 Department of Defense (DoD) military hospitals world-wide provided 71,800 cases with 83,197 reviews for quality of care evaluations by the Civilian External Peer Review Program (CEPRP). The majority (78,246 of 79,896) of completed peer review determinations (97.9%) generated agreement with care and documentation. It is concluded that health care in military treatment facilities is of high quality, meeting and generally exceeding accepted standards of care. It is also concluded that the DoD CEPRP offers conceptual and practical experience to guide the further evolution and integration of clinical peer review and quality improvement activities.

Peptide maps at picomolar levels obtained by reversed-phase high-performance liquid chromatography and pre-column derivatization with phenyl isothiocyanate. Microsequencing of Phenylthiocarbamyl Peptides

A new reversed-phase high-performance liquid chromatography approach to the production of analytical peptide maps by pre-column derivatization using phenylisothiocyanate is described. Tryptic peptide digests were derivatized with phenyl isothiocyanate to form the phenylthiocarbamyl peptides followed by reversed-phase high-performance liquid chromatographic analysis. The phenylthiocarbamyl peptides were separated by reversed-phase high-performance liquid chromatography with the conventional gradient elution system of water-acetonitrile containing trifluoroacetic acid. The sensitivity of detection of these peptide derivatives was within the range 5-10 pmol with a constant baseline at 254-260 nm. The isolated phenylthiocarbamyl peptides can be subjected to automatic Edman degradation. The effectiveness of this method was exemplified by microsequencing of phenylthiocarbamyl peptides isolated from tryptic digests of three different proteins: alpha-lactalbumin, beta-lactoglobulin and a lambda light-chain immunoglobulin.

Analysis of the activation process of porcine procarboxypeptidase B and determination of the sequence of its activation segment

The molecular events which lead to the proteolytic transformation of porcine procarboxypeptidase B (PCPB) in carboxypeptidase B (CPB) have been determined. Among pancreatic and other tested proteinases, trypsin is the only one capable of generating carboxypeptidase B activity from the zymogen, in vitro. In the first step of this process, trypsin produces cleavage at the boundary between the activation region and the CPB region. Subsequently, a definite sequence of cleavages occurs at the C-terminal end of the released activation segment of 95 residues, giving rise to characteristic intermediates and to a proteolytically resistant activation fragment of 81 residues. In this process, the newly formed CPB participates in the quick-trimming of the released activation peptides. Only a single CPB species is formed in the activation process. This fact and the inability of the released activation peptides to inhibit CPB--and, therefore, their inability to slow down the kinetics of appearance of CPB activity--are two important characteristics differentiating between the activation processes of procarboxypeptidases A and B. The sequence of the 95 residues (MW = 12,835) of the activation region of porcine PCPB has also been deduced, largely from the information obtained by Edman degradation of its fragments and in part by considerations of homology with the rat precursor. The porcine PCPB activation region contains a high percentage of acidic residues, lacks cysteines, methionines, and side-chain posttranslational modifications, and presents a low but significant homology (31%) with the corresponding sequence of porcine procarboxypeptidase A.

Characterization of the yeast acidic ribosomal phosphoproteins using monoclonal antibodies. Proteins L44/L45 and L44' have different functional roles

In order to characterize the acidic ribosomal proteins immunologically and functionally, a battery of monoclonal antibodies specific for L44, L44' and L45, the three acidic proteins detected in Saccharomyces cerevisiae, were obtained. Eight monoclonal antibodies were obtained specific for L45, three for L44' and one for L44. In addition, two mAbs recognizing only the phosphorylated forms of the three proteins were obtained. The specific immunogenic determinants are located in the middle region of the protein structure and are differently exposed in the ribosomal surface. The common determinants are present in the carboxyl end of the three proteins. An estimation of the acidic proteins by ELISA indicated that, in contrast to L44 and L45, L44' is practically absent from the cell supernatant; this suggests that protein L44' does not intervene in the exchange that has been shown to take place between the acidic proteins in the ribosome and in the cytoplasmic pool. It has also been found that, while IgGs specific for L44 and L45 do not inhibit the ribosome activity, the anti-L44' effectively blocks the polymerizing activity of the particles. These results show for the first time that the different eukaryotic acidic ribosomal proteins play a different functional role.

Nucleotide sequence of the exo-1,3-beta-glucanase-encoding gene, EXG1, of the yeast Saccharomyces cerevisiae

The nucleotide (nt) sequence of the Saccharomyces cerevisiae gene (EXG1) encoding extracellular exo-1,3-beta-glucanases (EXG) I and II was determined. An open reading frame of 1344 bp codes for a 448-amino acid (aa) polypeptide, with a calculated Mr of 51,307, which contains two potential N-glycosylation sites. The EXG1 DNA hybridizes to a 1.7-kb transcript whose 5' end maps to a position 98 bp upstream from the site of initiation of protein synthesis. Comparison of the N-terminal aa sequence deduced from the nt sequence with that of the purified EXGII revealed the existence of an extra 40-aa peptide in the precursor protein containing a Lys-Arg peptidase-processing site at the junction with the mature, extracellular form. The N-terminal region of the putative precursor is a very hydrophobic segment with structural features resembling those of signal peptides of secreted proteins. The Mr of the mature EXG polypeptide deduced from the nt sequence is 46,385. The 5'- and 3'-flanking regions of the EXG1 gene have structural features in common with other yeast genes.

Primary structure and inhibition of protein synthesis in eukaryotic cell-free system of a novel thionin, gamma-hordothionin, from barley endosperm

A new sulfur-rich and basic polypeptide, designated as gamma-hordothionin, has been isolated from barley endosperm by a semi-preparative purification consisting of extraction with a volatile salt solution followed by high-performance liquid chromatography using a reversed-phase C4 column. The isolated polypeptide was found to be homogeneous by micro-two-dimensional gel electrophoresis in the presence of sodium dodecyl sulfate. The complete primary structure of gamma-hordothionin was determined by automatic degradation of the intact, S-carboxymethylated and S-pyridylethylated gamma-hordothionin and fragments obtained by proteolytic cleavage. gamma-Hordothionin consists of a single polypeptide chain of 47 amino acids with a calculated molecular mass of 5250 Da and contains four disulfide bridges. gamma-Hordothionin inhibits translation in cell-free systems derived from mammalian (rabbit reticulocyte, mouse liver) as well as non-mammalian (Artemia embryo) cells, at several levels. At low concentrations (1-10 microM) the protein seems to affect mainly the polypeptide-chain-initiation process, although it might also act at the elongation level. At higher concentrations (20-80 microM) this inhibitor induces activation of an eukaryotic polypeptide-chain initiation factor 2 alpha-subunit (eIF-2 alpha) kinase in hemin-supplemented reticulocyte lysates, as does hemin deficiency. The presence of the disulfide bridges in gamma-hordothionin appears to be essential for the eIF-2 alpha kinase activation. Based on its similarity at both the structural and functional level with the different genetic variants of thionins (alpha and beta-thionins, from wheat and barley), gamma-hordothionin is a putative member of the thionin family.

gamma-Purothionins: amino acid sequence of two polypeptides of a new family of thionins from wheat endosperm

Two homologous sulfur-rich basic polypeptides form wheat endosperm, so-called gamma 1-purothionin and gamma 2-purothionin, are described. Purification involves extraction with volatile solvents and ammonium bicarbonate fractionation followed by reversed-phase high-performance liquid chromatography. The complete primary structure of these two polypeptides has been determined by automatic degradation of the intact, S-carboxymethylated gamma-purothionins and peptides obtained by enzymatic cleavage. gamma 1-Purothionin and gamma 2-purothionnin consist of 47 amino acids with an molecular weight of 5239 and 5151 Da, respectively and 8 cysteines organized in 4 disulfide bridges. They present a high degree of homology among themselves (89% of identity) and are the first two thionin-like polypeptides, so-called gamma-thionins, described from wheat endosperm.

Location and characterization of the three carbohydrate prosthetic groups of human protein HC

Three different carbohydrate prosthetic groups associated to three chymotryptic peptides, Q1, Q2 and Q3, were isolated from the reduced and carboxymethylated human protein HC. The first oligosaccharide forms an O-glycosidic linkage with a threonine residue at position 5 in the polypeptide chain of protein HC. The second and third carbohydrate prosthetic groups form N-linkages with asparagine residues at positions 17 and 96. Oligosaccharides present in Q1 contain 1 residue of NANA, 2 of GalNAc and 1 of Gal corresponding to the following structure: -O-GalNAc-GalNAc-Gal-NANA. Q2 contains 3 NANA, 9 GlcNAc, 2 Gal and 3 Man, and Q3 contains 2 NANA, 5 GlcNAc, 1 Gal and 2 Man. The sugar compositions of Q2 and Q3 oligosaccharides are compatible with that of the complex kind. The amount of oligosaccharides present in Q1, Q2 and Q3 corresponded respectively to 3.0%, 12.2% and 7.3% of the weight of protein HC. No difference was found between the carbohydrate composition of urinary and plasma protein HC.

Conformational changes in bacteriophage phi 29 connector prevents DNA-binding activity

In vitro DNA packaging activity in a defined system derived from bacteriophage phi 29 depends upon the chemical integrity of the connector protein p10. Proteolytic cleavage of p10 rendered the proheads inactive for DNA packaging. A similar treatment on isolated connectors abolished the DNA-binding activity of the native p10, but the general shape and size of the connector was not changed as revealed by electron microscopy. Analytical ultracentrifugation showed that the proteolyzed connectors had a smaller sedimentation coefficient, while amino acid analysis after dialysis of the proteolyzed p10 confirmed the loss of 16 and 19 amino acids from the amino and carboxy termini, respectively. Low angle X-ray scattering revealed that proteolysis was followed by a small decrease in the radius of gyration and a reorganization of the distal domain of the cylindrical inner part of the connector. Characterization of the cleavage sites in the primary sequence allowed us to propose the location of the DNA-binding domain in the connector model.

Complete purification of two identical Na(+)-pump inhibitors isolated from bovine hypothalamus and hypophysis

We have completely purified, in parallel, a low molecular weight, non-specific, non-lipidic, Na+,K(+)-ATPase inhibitory factor from bovine hypothalamic and pituitary tissues. In the final purification step we obtain, from both tissues, a single, homogeneous peak, with a maximal absorbance at 247 nm. This factor, at physiological concentrations of potassium (5-25 mM), inhibits in a dose-response manner Na+,K(+)-ATPase and displaces ouabain from its receptor at the enzyme structure. The factor isolated from both tissues is identical, being the specific activity per weight of tissue higher in hypophysis. No factor was found in cerebral cortex, used as tissue control.

Heat-stable translational inhibitor from rabbit reticulocyte lysates

We have purified to apparent homogeneity a heat-stable (HS) factor from the postribosomal supernatant of rabbit reticulocyte lysates [(1988) FEBS Lett. 236, 479-483]. HS inhibits translation in hemin-supplemented lysates and induces phosphorylation of the alpha-subunit of the eukaryotic initiation factor 2 as does hemin deficiency. The translational inhibition produced by addition of HS to hemin-containing reticulocyte lysates and the accompanying phosphorylation of the eIF-2 alpha subunit can be prevented or reversed by NADPH generators including glucose 6-phosphate, NADPH itself, and also by dithiols, e.g., dithiothreitol, but not by fructose 1,6-bisphosphate or by monothiols, e.g., 2-mercaptoethanol. When added to crude preparations of the proinhibitor form (proHCI) of the heme-controlled translational inhibitor (HCI), HS produces a pronounced increase of the HCI to proHCI ratio. It appeared possible that HS might be oxidized glutathione (GSSG) but this is not the case, for HS is not a substrate for highly purified glutathione reductase from rabbit erythrocytes. The spectral analysis of highly purified HS is consistent with the idea that HS could be a nucleotide derivative.

Naturally occurring serotype 2/subgroup II rotavirus reassortants in northern Brazil

Nine serotype 2 human rotavirus strains were isolated in a community-based longitudinal study in Northern Brazil. Five of these strains had a 'long' RNA electrophoretic pattern and all five strains were determined to belong to subgroup II by ELISA assay, in contrast to properties common to serotype 2 human rotaviruses previously characterized. Hybridization studies of one of these unusual strains with 32P-labelled mRNAs derived from the prototype human strains Wa (serotype 1, subgroup II) and S2 (serotype 2, subgroup I) suggested that it was generated by a reassortment event in nature, in which a subgroup II, 'long' electropherotype rotavirus exchanged its serotype-specific gene and gene number 10 for the equivalent genes from a serotype 2, 'short' electropherotype virus.