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H Hohjoh

Publications and source records attributed to H Hohjoh.

29 records · Page 2Linked to original sources
PubMed1999

Possible association of human leucocyte antigen DR1 with delayed sleep phase syndrome.

The study investigated the human leucocyte antigen (HLA), types A, B and DR, of 42 patients with delayed sleep phase syndrome (DSPS) and compared the frequencies of the antigens with those in 117 healthy controls. The comparison revealed that the gene frequencies and positivities of HLA-A, -B and -DR, except for DR1, had no significant differences between the patients and controls. The frequency of HLA-DR1 was increased in the DSPS patients as compared with that in the healthy controls (P = 0.0069 in positivity). Although the corrected P-value (0.069) for multiple comparisons almost reached the significance level, the results indicated a possible association of the HLA-DR1 antigen with DSPS. This study suggests that there are genetic predispositions to DSPS.

Adolescent↗
PubMed1997

Sequence-specific single-strand RNA binding protein encoded by the human LINE-1 retrotransposon.

Previous experiments using human teratocarcinoma cells indicated that p40, the protein encoded by the first open reading frame (ORF) of the human LINE-1 (L1Hs) retrotransposon, occurs in a large cytoplasmic ribonucleoprotein complex in direct association with L1Hs RNA(s), the p40 RNP complex. We have now investigated the interaction between partially purified p40 and L1Hs RNA in vitro using an RNA binding assay dependent on co-immunoprecipitation of p40 and bound RNA. These experiments identified two p40 binding sites on the full-length sense strand L1Hs RNA. Both sites are in the second ORF of the 6000 nt RNA: site A between residues 1999 and 2039 and site B between residues 4839 and 4875. The two RNA segments share homologous regions. Experiments involving UV cross-linking followed by immunoprecipitation indicate that p40 in the in vitro complex is directly associated with L1Hs RNA, as it is in the p40 RNP complex found in teratocarcinoma cells. Binding and competition experiments demonstrate that p40 binds to single-stranded RNA containing a p40 binding site, but not to single-stranded or double-stranded DNA, double-stranded RNA or a DNA-RNA hybrid containing a binding site sequence. Thus, p40 appears to be a sequence-specific, single-strand RNA binding protein.

Amino Acid Sequence↗
PubMed1997

Ribonuclease and high salt sensitivity of the ribonucleoprotein complex formed by the human LINE-1 retrotransposon.

P40 is encoded by the first open reading frame of the human LINE-1 retrotransposon and is found in a large cytoplasmic ribonucleoprotein (RNP) complex, the p40 RNP-complex, in association with LINE-1 RNA(s) in human teratocarcinoma cell lines. We report here investigations on the stability of the p40 RNP-complex against various nucleases and high salt (0.5 M NaCl) treatment. The results indicate that (1) the p40 RNP-complex is dissociated after ribonuclease or high salt treatment, (2) DNase I does not disrupt the complex, (3) after dissociation of the complex, p40 maintain protein-protein interactions but in smaller complexes, and (4) p40 is not associated with the LINE-1 RNA(s) after high salt treatment. These observations suggest that the RNA molecule(s) is(are) essential for the stability of the large p40 complex and that the complex has a structure which allows various nucleases to reach the RNA. These features are distinct from those of typical virus and virus-like particles of retroviruses and other retrotransposons, respectively. Together with the fact that no significant sequence homology exists between p40 and the gag and gag-like proteins, it is likely that the p40 RNP-complex is structurally different from the typical virus and virus-like particles.

Blotting, Western↗
PubMed1996

Cytoplasmic ribonucleoprotein complexes containing human LINE-1 protein and RNA.

P40 is the protein encoded by the first open reading frame (ORF1) of the human LINE-1 (L1Hs) retrotransposon; it is 338 amino acids long, has a leucine zipper motif and has been found in human teratocarcinoma cell lines and some tumor cells. In this report, we describe properties of p40 in the human teratocarcinoma cell lines NTera2D1 and 2102Ep. The results indicate that: (i) most of p40 occurs in large multimeric cytoplasmic complexes, (ii) L1Hs RNA is associated with the p40 complexes, (iii) the complexes are dissociated by ribonuclease and (iv) p40 is a novel RNA-binding protein. Cross-linking experiments with full-length and truncated p40 produced in Escherichia coli also showed that: (i) p40 itself can form a multimeric complex larger than 250 kDa, (ii) the leucine zipper motif and the region conserved among the predicted ORF1 polypeptides of mammalian LINE-1s participate in complex formation and (iii) the amino terminal region is important for the stability of complex formation. Analysis of the amino acid sequence of p40 suggests that long segments of the molecule can assume an alpha-helical configuration including the leucine zipper and the conserved region. The evidence presented here suggests that the p40 complex is a ribonucleoprotein complex containing L1Hs RNA(s) and that protein-protein interactions in which alpha-helix structures participate, for example coiled-coils, may occur in the complex.

Amino Acid Sequence↗
PubMed1993

Pulsed-field polyacrylamide gel electrophoresis: basic phenomena and applications.

Pulsed-field gel electrophoresis (PFGE) using polyacrylamide gels, termed pulsed-field polyacrylamide gel electrophoresis (PF-PAGE), had been developed for the effective separation of linear DNAs from circular ones [1]. The first generation PF-PAGE employed horizontal polyacrylamide gels run in a contour-clamped homogeneous electric field (CHEF) apparatus. The second generation system, using a vertical slab gel in a discontinuous buffer system and field inversion gel electrophoresis (FIGE), was found to be easier to handle and requires a much shorter time for separation than the previous one [2]. In this report, basic aspects of the second generation PF-PAGE, such as the effects of a discontinuous buffer system and field inversion on the DNA migration in polyacrylamide gels, were investigated. The results indicate that the periodic inversion of electric field can broaden the resolving capability of polyacrylamide gels, enabling DNAs that otherwise fail to enter polyacrylamide gels to be resolved in such systems. Successful and possible applications of PF-PAGE techniques are also discussed.

Base Sequence↗
PubMed1993

Mesothelial splenic cyst.

A 29-year-old female was admitted because of thrombocytopenia and an abdominal mass which was palpated 5 finger breadths below the left costal margin. A computed tomographic scan of the abdomen revealed splenomegaly with a large calcified cystic lesion. The spleen was removed and the pathological examination disclosed that the cyst was monolocular and the wall was of mesothelial origin.

Adult↗
PubMed1990

Selective cloning and sequence analysis of the human L1 (LINE-1) sequences which transposed in the relatively recent past.

L1 (LINE-1), a long interspersed repetitive DNA family of mammalian genomes, is thought to be a sequence family derived from a retrotransposon-like element(s), but its actively transposable unit(s) has not been identified yet. We developed a novel method for selective isolation of the human L1 sequences which transposed in a relatively recent past and may have still retained a feature of the 'active L1' unit. From the inspection of the nucleotide sequences, we conjectured that the 'active L1' or 'nearly active L1' units should have a high content of the CpG dinucleotide sequence, a mutation hot spot sequence, and contain several sites for rare cutters such as BssH II and Nar I at their 5' terminal regions. Using these rare cutter sites as selection markers, the L1 sequences were isolated, which had the high content of CpG at the 5' terminal regions and over 90% homology to L1 transcripts found in a human teratocarcinoma cell line. These L1s were shown to be 'relatively new L1' units which had integrated into chromosomes within these several million years during evolution. From the sequence data of these L1s and L1 cDNA, a consensus sequence of the 5' terminal region of high CpG L1s were constructed. A region of the consensus sequence showed about 69% homology to the 5' terminal region of Drosophila jockey element.

Animals↗
PubMed1984

[Arteriovenous malformations of the cervical spinal cord--with special reference to CT study].

Arteriovenous malformation (AVM) of the cervical spinal cord has been known to constitute 5-13% of all spinal AVMs. In contrast to the AVMs located in thoracic or thoraco-lumbar regions, cervical AVM has several characteristic features such as preponderance in younger generation, high incidence of subarachnoid hemorrhage, intramedullary location of the nidus usually fed by the anterior spinal arterial system. We reported three cases of cervical AVMs, which located intramedullary at the levels of C4-C6, C1-C4 and C1-C2, respectively. Although selective angiography (vertebral artery, thyrocervical artery, costocervical artery) was essential for the diagnosis of these lesions, computerized tomographic (CT) study with both intrathecal injection of metrizamide and intravenous infusion of contrast material (dynamic and static study) was found to be extremely advantageous in detecting the topography of AVMs in the concerned horizontal planes of the spinal cord. Removal of AVM was given up in one case because of its possible involvement of the anterior spinal artery and central artery shown by CT scan. Removal of AVMs were performed in other two cases. A lateral approach was tried in one case with the AVM located in C1-C2 level, in which CT scan revealed not only an intramedullary but the associated extramedullary AVM in ventrolateral surface of the spinal cord. This operative approach was found to involve less bone removal and markedly reduce spinal cord manipulation necessary to deal with ventrally situated high cervical lesions, compared with a posterior approach with laminectomy.

Adult↗