Biomedical subjects

H Komano

Publications and source records attributed to H Komano.

At least 37 records · Page 2Linked to original sources

PubMed1993

Two alternative forms of cDNA encoding CD34.

By expression cloning using FACS, we have isolated cDNA clones encoding human CD34 from a megakaryoblastoid cell line. The predicted amino acid sequence of CD34 revealed the type I transmembrane protein consisted of a leader peptide (31 residues), an extracellular domain (258 residues), a transmembrane domain (23 residues) and a cytoplasmic domain of 73 residues. In addition, a second form of cDNA that has 194 bp insertion in the cytoplasmic region was isolated. The analysis of genomic DNA showed that this sequence is inserted between the predicted transmembrane and cytoplasmic exons due to an alternative usage of an imperfect 5' splice acceptor site in the 5' flanking region of the cytoplasmic exon. The insertion brings a stop codon so that the protein encoded by this type of mRNA has only 16 residues in the cytoplasmic domain. This truncated form of CD34 molecule can be expressed on the cell surface, and its expression seems to change in association with cell differentiation. A search of the National Biomedical Research Foundation Protein Sequence Database (NBRF) with the Predicted amino acid sequence of CD34 did not reveal homology to any known protein. Thus, the CD34 molecule represents a novel type of cell surface molecule that may have a role in early differentiation process of hematopoietic stem cells.

Amino Acid Sequence↗

PubMed1992

The fate of the prosegment in the acute-phase and programmed synthesis of sapecin, an antibacterial peptide of the flesh fly (Sarcophaga peregrina).

The nucleotide sequence of sapecin cDNA suggested that this antibacterial peptide of the flesh fly (Sarcophaga peregrina) is produced from preprosapecin by post-translational processing. We examined the production of sapecin and its prosegment by radioimmunoassay under two different physiological conditions in which its gene is activated, assuming that the prosegment has some biological role. Results suggested that the prosegment is degraded selectively during production of sapecin. We also found that imaginal discs synthesize sapecin when cultured in the presence of 20-hydroxyecdysone.

Amino Acid Sequence↗

PubMed1992

Evidence for an increase in positive surface charge and an increase in susceptibility to trypsin of Sarcophaga lectin (from the flesh fly, Sarcophaga peregrina) on its interaction with galactose, a hapten sugar of the lectin.

When Sarcophaga lectin (from the flesh fly, Sarcophaga peregrina), an insect humoral lectin, was eluted from a column of DEAE-cellulose in the presence of galactose (a hapten sugar of this lectin), it emerged at a lower salt concentration than when galactose was absent. In the presence of galactose the lectin was, in addition, more susceptible to trypsin digestion. The lectin was found to have an affinity for basic proteins such as histone H3 and sarcotoxin IA, but this property was lost in the presence of galactose. These results suggested that the lectin changes its conformation on interaction with galactose. This change is suggested to result in the exposure of some hidden lysine and/or arginine residues.

Amino Acid Sequence↗

PubMed1991

Involvement of sapecin in embryonic cell proliferation of Sarcophaga peregrina (flesh fly).

Addition of antibodies against sapecin to the culture medium of NIH-Sape-4 cells derived from a Sarcophaga embryo greatly inhibited cell proliferation, whereas addition of sapecin stimulated cell proliferation. These results suggest that sapecin is involved in the proliferation of embryonic cells of Sarcophaga. Sapecin is known to have potent antibacterial activity, so it seems to have two different biological functions: i.e. protection against bacterial infection and stimulation of embryonic cell proliferation.

Animals↗

PubMed1991

Purification of a stage-specific and sequence-specific DNA-binding protein for the arylphorin gene of Sarcophaga peregrina.

A protein that binds specifically to the nucleotide sequence ACCACAACA located at residues -247 to -255 upstream of the +1 site of the arylphorin gene of Sarcophaga peregrina was purified to homogeneity from fat body nuclei of third instar larvae. This DNA-binding protein consisted of two subunits with molecular masses of 40 kDa and 42 kDa, respectively. Accurate transcription initiation of a truncated arylphorin gene in a nuclear extract of NIH-Sape-4 cells, an embryonic cell line of Sarcophaga, was significantly enhanced in the presence of the purified DNA-binding protein.

Animals↗

PubMed1991

Involvement of Sarcophaga lectin in the development of imaginal discs of Sarcophaga peregrina in an autocrine manner.

The imaginal discs of Sarcophaga were found not to develop normally in the presence of galactose, a hapten sugar of Sarcophaga lectin, or anti-Sarcophaga lectin antibody. Wing and leg discs cultured with these substances became morphologically abnormal and no imaginal discs reached the stage of terminal differentiation, even in the presence of 20-hydroxyecdysone. The development of the imaginal discs was shown to be autonomously regulated in an autocrine manner by Sarcophaga lectin; namely Sarcophaga lectin was secreted by the imaginal discs in the presence of 20-hydroxyecdysone, and the stimulus of self-induced Sarcophaga lectin seemed to be indispensable for further development of the imaginal discs. Sarcophaga lectin was originally found as a defense protein, but these results show that it plays independent roles in both defense and development.

Animals↗

PubMed1990

1H nuclear magnetic resonance study of the solution conformation of an antibacterial protein, sapecin.

The solution conformation of an antibacterial protein sapecin has been determined by 1H nuclear magnetic resonance (NMR) and dynamical simulated annealing calculations. It has been shown that the polypeptide fold consists of one flexible loop (residues 4-12), one helix (residues 15-23), and two extended strands (residues 24-31 and 34-40). It was found that the tertiary structure of sapecin is completely different from that of rabbit neutrophil defensin NP-5, which is homologous to sapecin in the amino acid sequences and also has the antibacterial activity. The three-dimensional structure determination has revealed that a basic-residue rich region and the hydrophobic surface face each other on the surface of sapecin.

Amino Acid Sequence↗

PubMed1989

Stage-specific detection of a DNA-binding protein for the storage protein gene of Sarcophaga peregrina.

A nuclear extract of fat body prepared from third instar larvae of Sarcophaga peregrina (flesh fly) was found to contain a DNA-binding protein that specifically bound to 5'-upstream region of the storage protein (arylphorin) gene. This protein was found only in larvae harvested 46 h after larval emergence, indicating that its appearance was strictly regulated by the developmental stage of the insect. Since the storage protein gene is actively transcribed in the fat body at this stage, this protein is probably a specific transcription factor for the storage protein gene. DNase I footprinting analysis showed that the nucleotide sequence of the binding site of this protein is ACCACAACA, which is located at residues -247 to -255 upstream of the +1 site. Results indicated that formation of the DNA-protein complex required Zn2+.

Animals↗

PubMed1989

Tumor induction in mice administered neonatally with 1,2-dimethylhydrazine.

1,2-Dimethylhydrazine was given subcutaneously to neonatal ICR mice, and animals were observed for one year. The tumors of lung and liver, malignant lymphoma, and other tumors were induced. In the mice given DMH 30 mg/kg of body weight, two mice developed colonic tumor, and the incidence of colonic tumor was low.

1,2-Dimethylhydrazine↗

PubMed1988

Identification and characterization of Sarcophaga lectin receptor on the surface of murine macrophages by use of monoclonal antibodies.

The structure of Sarcophaga lectin receptor on the surface of murine macrophages was analyzed using monoclonal antibodies. This receptor was found by gel filtration to have a molecular weight of 460 kDa. SDS-polyacrylamide gel electrophoresis showed that this receptor consists of two subunits of 170 kDa and 110 kDa. The results indicated that it is probably a heterotetramer of two molecules of each subunit. Two monoclonal antibodies recognized epitopes in the 110 kDa subunit, and one of them specifically inhibited the binding of Sarcophaga lectin to macrophages and the cytotoxic reaction mediated by this lectin in the presence of macrophages. Therefore, it is likely that the 110 kDa protein in the receptor plays a role in activation of macrophages by this lectin.

Animals↗

PubMed1987

Purification of Sarcophaga (fleshfly) lectin and detection of sarcotoxins in the culture medium of NIH-Sape-4, an embryonic cell line of Sarcophaga peregrina.

An established cell line originating from a Sarcophaga peregrina (fleshfly) embryo, NIH-Sape-4, was found to synthesize mRNAs for Sarcophaga lectin and sarcotoxin IA, but not those for storage protein or 25 kDa protein. These four proteins are known to be synthesized in the fat-body of third-instar larvae, and the two former in particular are known to participate in the defence mechanism of this insect and to be induced in response to injury of the body wall. Thus the embryonic cell line NIH-Sape-4 synthesizes certain defence proteins constitutively. This cell line will be useful for large-scale purification of Sarcophaga lectin, since 50 micrograms of purified Sarcophaga lectin could be obtained from about 400 ml of culture medium.

Animals↗

PubMed1987

Purification of a lectin from the hemolymph of Chinese oak silk moth (Antheraea pernyi) pupae.

A lectin with affinity to galactose was purified to homogeneity from the hemolymph of diapausing pupae of the Chinese oak silk moth, Anteraea pernyi. The molecular mass of this lectin was 380,000 and it formed an oligomeric structure of a subunit with a molecular mass of 38,000. The hemagglutinating activity in the hemolymph was found to increase with time after immunization with E. coli. Studies with antibody against the purified lectin showed that increase in the hemagglutinating activity was due to the same lectin, suggesting that the amount of the lectin increased in response to intrusion of foreign substances. The function of this lectin in the defence mechanism is discussed.

Animals↗

PubMed1987

Purification of sarcotoxin III, a new antibacterial protein of Sarcophaga peregrina.

A glycine-rich antibacterial protein with a molecular mass of 7,000 termed sarcotoxin III, was purified to homogeneity from the hemolymph of third instar larvae of Sarcophaga peregrina. When the hemolymph was fractionated, this protein was recovered in the same fraction as sarcotoxin I, a group of potent antibacterial proteins that have been purified. But, it was clearly different from sarcotoxin I in amino acid composition and molecular mass. Sarcotoxin III was shown to be induced in the hemolymph in response to injury of the larval body wall.

Amino Acids↗

PubMed1986

Molecular cloning of a cDNA and assignment of the C-terminal of sarcotoxin IA, a potent antibacterial protein of Sarcophaga peregrina.

A previous paper described the complete amino acid sequences of sarcotoxins IA, IB and IC, which are a group of potent antibacterial proteins with almost identical primary structures produced by Sarcophaga peregrina (fleshfly) larvae [Okada & Natori (1985) J. Biol. Chem. 260, 7174-7177]. The present paper describes the cDNA cloning and complete nucleotide sequencing of a cDNA clone for sarcotoxin IA. The C-terminal amino acid residue of sarcotoxin IA deduced from the nucleotide sequence was glycine, whereas it was found to be arginine by amino acid sequencing of purified sarcotoxin IA. Analysis of the elution profiles on h.p.l.c. of the synthetic derivatives of sarcotoxin IA showed that the C-terminal amino acid residue of authentic sarcotoxin IA is amidated arginine, which is probably produced by enzymic cleavage of terminal glycine.

Amino Acid Sequence↗

PubMed1986

Participation of common surface receptor(s) in the activation of murine macrophages by Sarcophaga lectin and wheat germ agglutinin.

Mouse peritoneal macrophage surface proteins which bind Sarcophaga lectin were studied. Two major binding proteins with molecular masses of 170 and 110 kDa were identified. Sarcophaga lectin and wheat germ agglutinin were found to share common binding proteins for activating macrophages, although their hapten sugars are different. Antibody raised against the Sarcophaga lectin-binding proteins inhibited both the production of tumor-specific cytotoxic protein by the macrophage-like cell line J774.1 cells and the lectin-dependent macrophage-mediated cytotoxic reaction induced by Sarcophaga lectin or wheat germ agglutinin. Thus the 170-kDa and/or 110-kDa protein is important in activation of macrophages.

Animals↗

PubMed1985

Cloning and sequencing of cDNA of Sarcophaga peregrina humoral lectin induced on injury of the body wall.

A previous paper described the purification of a lectin induced in the hemolymph of larvae of Sarcophaga peregrina (flesh-fly) on injury of their body wall (Komano, H., Mizuno, D., and Natori, S. (1980) J. Biol. Chem. 255, 2919-2924). This paper describes cDNA cloning and the complete nucleotide sequence of the gene for Sarcophaga lectin. Although active lectin consists of alpha and beta subunits in a molar ratio of 2:1, the fat body of injured larvae was found to contain only mRNA for the alpha subunit, suggesting that these two subunits are derived from a common gene and that the alpha subunit is converted to the beta subunit post-translationally. The alpha subunit was found to consist of 260 amino acid residues with an additional signal sequence of 19 or 23 amino acid residues.

Amino Acid Sequence↗

PubMed1985

Participation of Sarcophaga peregrina humoral lectin in the lysis of sheep red blood cells injected into the abdominal cavity of larvae.

Sarcophaga lectin which is induced in the hemolymph of Sarcophaga peregrina (flesh-fly) larvae when their body wall is injured with a hypodermic needle, was shown to participate in the lysis of sheep red blood cells introduced into the abdominal cavity of the larvae. This finding indicates that humoral lectin plays a role in the defence mechanism of invertebrates. The lysis of sheep red blood cells was enhanced greatly by preinjection of red blood cells, but less by preinjection of other cells. Thus the defence mechanism of this insect seems to be able to distinguish red blood cells from other cells.

Animals↗

PubMed1985

Identification of target proteins participating in a lectin-dependent macrophage-mediated cytotoxic reaction.

Membrane proteins of mouse macrophages and mammary tumor cells having affinity to Sarcophaga lectin were isolated by affinity chromatography. The electrophoretic profiles and antigenicities of lectin-binding proteins from macrophages and tumor cells were different. Antibody raised against tumor cell lectin-binding proteins inhibited both the binding of the lectin to tumor cells and the lectin-dependent macrophage-mediated cytotoxic reaction. However, it did not inhibit the binding of the lectin to macrophages. It was suggested that the same lectin molecule transmitted different stimuli to macrophages and tumor cells via different receptor proteins.

Animals↗