Biomedical subjects

Machiko Sawada

Publications and source records attributed to Machiko Sawada.

5 recordsLinked to original sources

PubMed2006

Transformation of poplar (Populus alba) plastids and expression of foreign proteins in tree chloroplasts.

Plastid transformation offers several unique advantages compared with nuclear genome transformation, such as high level of transgene expression within plastids, expressing multiple transgenes as operons, lack of position effect due to site-specific transgene integration, and reducing risks of gene flow via pollen due to maternal inheritance of the plastid genome. Plastid transformation has been applied to several herbal species, but as yet there are no applications to tree species. We report here the first successful plastid transformation in a tree species, Populus alba. A vector for plastid transformation of poplar (Populus alba) was constructed, which carried the spectinomycin resistance gene and the green fluorescence protein gene as marker genes. In the regenerated shoots, the site-specific integration of foreign genes and the establishment of a high homoplastomic state were confirmed. Immunoblot analysis and histological observations corroborated the accumulation of green fluorescence protein in chloroplasts. The establishment of a plastid transformation system in poplar provides a novel tool for tree biotechnology.

Chloroplasts↗

PubMed2006

Multiple vacuolar sorting determinants exist in soybean 11S globulin.

The sorting determinants of glycinin, a soybean (Glycine max) 11S globulin, which mediates protein targeting to the protein storage vacuole (PSV), were investigated in maturing soybean cotyledons by transient expression assays. A C-terminal stretch of 10 amino acids of A1aB1b, a glycinin group I subunit, was sufficient to direct green fluorescent protein (GFP) to the PSV. This peptide may correspond to a C-terminal vacuolar sorting determinant (ctVSD). Because functional inhibition of this putative ctVSD of A1aB1b did not block PSV sorting of A1aB1b, we used the three-dimensional structure of A1aB1b to identify candidates for a sequence-specific determinant (ssVSD). We found that the sequence downstream of disordered region 4 could direct GFP to the PSV and that Ile-297 is critical for sorting. However, functional inhibition of the ctVSD, combined with the Ile297Gly mutation, did not abolish the vacuolar sorting of A1aB1b, suggesting that A1aB1b has a third sorting determinant in addition to ctVSD and ssVSD. A glycinin group II subunit, A3B4, lacked a ctVSD but contained a VSD reminiscent of an ssVSD and an additional sorting determinant. We also demonstrate, by expression of dominant negative mutants of small GTPases and drug treatment experiments, that the trafficking of A1aB1b is COPII vesicle-dependent and wortmannin- and brefeldin A-sensitive.

ADP-Ribosylation Factor 1↗

PubMed2004

Longitudinal follow-up of patients with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis.

BACKGROUND AND OBJECTIVES: Although immunochemotherapy has been reported to be an effective initial treatment for patients with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH), the long-term outcome of these patients remains unknown. The main purpose of this study was to determine the outcome of the EBV-HLH patients treated between 1992 and 2001. DESIGN AND METHODS: During this period, a total of 78 EBV-HLH patients were consecutively registered in 3 separate studies. The rates of initial response, reactivation, and survival as well as causes of death were analyzed. The outcome of the patients who received hematopoietic stem cell transplantation was also studied. RESULTS: With a median follow-up of 43 months, clinical reactivation was noted in 13 patients (19.4%) and a total of 12 patients needed hematopoietic stem cell transplantation, of whom 9 are alive and well. There had been 19 deaths: early deaths were due to hemorrhages and infections (n=11), while late deaths were related to late reactivation (n=4), transplant-associated causes (n=3) and secondary leukemia (n=1). Overall, after a median follow-up of 43 months, 59 (75.6%) of the 78 patients are alive and well. INTERPRETATION AND CONCLUSIONS: The majority of successfully treated EBV-HLH patients have a good outcome and remain disease-free.

Adolescent↗

PubMed2003

Molecular and structural analysis of electrophoretic variants of soybean seed storage proteins.

Soybean (Glycine max L.) storage proteins are composed mainly of two major components, beta-conglycinin and glycinin. Electrophoretic variants of the beta subunit of beta-conglycinin and the A3 polypeptide of glycinin were detected on SDS-PAGE, and designated them as beta* and A3*, respectively. beta* and A3* exhibited higher and lower mobilities, respectively, than the common beta subunit and A3 polypeptide. The N-terminal nine and 10 amino acid sequences of beta* and A3* were completely identical to the previously reported sequences of the beta subunit and the A3 polypeptide, respectively. Analysis using concanavalin A-horseradish peroxidase and treatment with N-glycosidase indicated that glycans were not responsible for the difference in electrophoretic mobility of beta* or A3*. Furthermore, five clones of beta* or beta and three clones of A3*, respectively, were sequenced but we could not detect deletions and insertions except for a single or a few amino acid substitutions as compared with the common beta subunit and A3 polypeptide. These results indicate that a single or a few amino acid substitution affects the electrophoretic mobilities of beta* and A3*.

Amino Acid Sequence↗

PubMed2002

A novel missense mutation in the DKC1 gene in a Japanese family with X-linked dyskeratosis congenita.

The authors report 2 male patients with dyskeratosis congenita (DC) in a Japanese kindred. Sequencing of the complementary DNA of the dyskerin gene (DKC1) revealed a T-to-C transition at nucleotide 1285 in exon 12 that resulted in a novel missense mutation L398P. Despite harboring the same mutation in the DKC1 gene, one patient had significantly milder hematological symptoms than the other, indicating that there may be other factors that determine the severity of DC.

Cell Cycle Proteins↗