Biomedical subjects

A Kondoh

Publications and source records attributed to A Kondoh.

4 recordsLinked to original sources

PubMed1992

Human ETS1 oncoprotein. Purification, isoforms, -SH modification, and DNA sequence-specific binding.

The human ETS1 proto-oncogene proteins have been isolated from the T-cell leukemia line, CEM, by immunoaffinity chromatography and their identity confirmed by NH2-terminal amino acid sequencing. Incubation of CEM cells with N alpha-p-tosyl-L-lysine chloromethyl ketone (TLCK) indicates that ETS proteins can be modified in their cellular context and that pretreatment of the cells with N-ethylmaleimide (NEM) protects ETS1 proteins from TLCK modification. These data show that ETS1 proteins can exist in at least two different states, -SH-available and -SH-protected. Renatured human ETS1 has DNA sequence-specific binding to the PEA3 (CAGGAAGT) motif. The ETS1.PEA3 complex can be observed by electrophoretic mobility shift assays (EMSA). Purified ETS1 retards a band which is exactly the same size as a complex that is retarded from nuclear extracts prepared from CEM cells. Reduced ETS1 is required to form the ETS1.PEA3 complex, however; modification of the ETS1 -SH groups by either NEM or by TLCk does not inhibit formation of the complex. The ETS1.PEA3 complex formed with TLCK-modified ETS1 has a slower mobility than the complex formed with unmodified ETS1. Zone sedimentation analysis of purified ETS1 indicates that it is the monomer of ETS1 which binds to the PEA3 oligonucleotide.

Amino Acid Sequence↗

PubMed1992

Stimulative effect of non-parenchymal liver cells on ability of tyrosine aminotransferase induction in hepatocytes.

Hepatocytes and non-parenchymal liver cells were isolated from adult rat liver and co-cultured for 48 hours as a monolayer on polystyrene culture dishes. The ability of tyrosine aminotransferase (TAT) induction in hepatocytes was examined in the presence of dexamethasone and dibutyryl cAMP. Non-parenchymal cells greatly enhance the ability of TAT induction of hepatocytes. A soluble factor with molecular weight of more than 10,000 is responsible for this enhancement, because conditioned medium prepared from non-parenchymal cells is also stimulatory. Non-parenchymal cells restored the ability in hepatocytes damaged with the addition of D-galactosamine. Conditioned medium prepared from non-parenchymal cells treated with D-galactosamine had higher activity of enhancement than the medium from normal cells. The soluble factor might be released in response to some signal of injury. Hepatocytes and non-parenchymal cells were immobilized within Ca-alginate, and although immobilized hepatocytes rapidly lost the ability to induce TAT, hepatocytes co-immobilized with non-parenchymal cells maintained the ability during 4 days of culture. These results indicated that non-parenchymal liver cells, as well as hepatocytes, could be used to construct a bioartificial liver support system.

Animals↗

PubMed1992

[Preliminary clinical trial of intrathecal rt-PA (TD-2061) for the prevention of cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage].

The results of preliminary clinical trial (a multicenter, open-label, dose escalation study) of intrathecal recombinant tissue plasminogen activator (rt-PA) for the prevention of cerebral vasospasm were reported. Seventeen patients admitted within 48 hours of subarachnoid hemorrhage (SAH) were enrolled in this study. Patients ranged from 42 to 69 years of age. All cases enrolled were classified in clinical grade II, III or IV according to the classification of Hunt and Kosnik and in group 3 or 4 according to Fisher's CT grading scale. Surgery for clipping the aneurysms were performed and a small silicone catheter was left in the subarachnoid space. Twenty four hours after the surgery intrathecal bolus infusion of rt-PA was started through the silicone catheter at 6-hour intervals for 3 days. Patients were divided into 4 groups based on the dosage of rt-PA for each infusion. The dosage of rt-PA for each infusion and a number of cases in each group was as follows; 25 KIU in 4 cases, 75 KIU in 6 cases, 200 KIU in 4 cases and 600 KIU in 3 cases. There was no significant difference in the clearance of subarachnoid clots between four groups. However, the occurrence of both symptomatic and angiographic vasospasm was less in the 75 KIU group than in other three groups. Intracranial bleeding complications were noted in 4 patients (1/6 in the 75 KIU group, 2/4 in the 200 KIU group and 1/3 in the 600 KIU group). Serial coagulation studies demonstrated no evidence of systemic fibrinolysis. Disorientation was noted in 2 out of 3 patients of the 600 KIU group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

High-affinity DNA-protein interactions of the cellular ETS1 protein: the determination of the ETS binding motif.

ETS1 protein purified from CEM cells was used to select its optimum DNA-binding sequence (pu) G/CCaGGA-AGTc (py). The sequence CCGGAAGT (ETS1-3) was preferred 5:1 over CAGGAAGT (PEA3). Quantitative electrophoretic mobility-shift assays (EMSA) indicated that the purified ETS1 protein binds to either ETS1-3 or PEA3 oligonucleotide probes with high affinity (Ka = 0.5-4.0 x 10(10) M-1) and that the purified ETS1 has different binding capacities for ETS1-3 and PEA3 oligonucleotide probes. The ETS1 protein binds 2-5 times more ETS1-3 than PEA3. Competitive binding experiments showed that the ETS1-3 and PEA3 probes effectively compete for the binding of ETS1-3. However, changing the core DNA-binding sequence from GGAA to AGAA eliminates competition. Since the human ETS1 protein selected the same DNA sequence from a mixture of random oligonucleotides as did the Drosophila E74A protein (one of the most divergent members of the ETS family), this strongly suggests that all proteins containing the ETS 85 amino acid domain (sequences which define the ETS family) will bind to the same sequence.

Base Sequence↗