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Biomedical subjects

Y Gotoh

Publications and source records attributed to Y Gotoh.

At least 217 records · Page 12Linked to original sources
PubMed1987

Signals for the selection of a splice site in pre-mRNA. Computer analysis of splice junction sequences and like sequences.

To evaluate the importance of the surrounding nucleotide sequence in the selection of a splice site for mRNA, we have carried out computer studies of eukaryotic protein genes whose entire nucleotide sequences were available. A splice site-like sequence that has a significant homology to the consensus splice junction sequences is frequently found within an intron and exon. It is found that the higher the homology of a candidate donor site sequence to the nine-nucleotide consensus sequence, the higher is its probability of being a donor site. For most of the donors, the stability of presumed base-pairing with U1-RNA is higher than that of donor-like sequences, if any, in the adjacent exon and intron. However, homology of a candidate acceptor sequence to the 15-nucleotide consensus is a poor criterion of an acceptor site. The presence of a sequence that could serve as a branch-point 18 to 37 nucleotides before an acceptor does not seem to be critical in distinguishing it from an acceptor-like sequence. For genes of human, rat, mouse and chicken, respectively, nucleotide frequencies around splice junctions of many genes have been calculated. They seem to be different at some positions around a donor site from species to species. The acceptors for these vertebrates have longer pyrimidine-rich regions than the previous consensus sequence. The newly derived nucleotide frequencies were used as the standard to calculate the weighted homology score of a candidate splice site sequence in a gene of the four species. This weighted homology score of the 40 to 60-nucleotide intron-exon sequence is a much better criterion of an acceptor. These results suggest that the most important signal in the selection of a splice resides in the surrounding nucleotide sequence. It is also suggested that the surrounding nucleotide sequence alone is not generally sufficient for the selection.

Animals↗
PubMed1987

Transferrin variants in Japan and New Zealand. Report of an unusually sialyzed TF variant.

The genetic polymorphism of transferrin (TF) was studied in 2,167 Japanese individuals and in 448 New Zealanders. The three TF C subtypes were identified, but TF C3 was absent from Japanese populations. In addition, three TF B and six TF D variants were observed, each of which occurred either in Japanese or in New Zealanders. Stepwise removal of N-acetyl-neuraminic acid (NANA) with neuraminidase revealed that the most cathodal variant TF DShinnanyo found in a Japanese family was characterized by having only two NANA residues.

Gene Frequency↗
PubMed1987

[A case of a primary localized amyloidosis (amyloid tumor) of the renal pelvis and ureter].

A 62-year-old woman complaining of asymptomatic hematuria was hospitalized. Although a cytologic examination of the urine was negative, abnormal findings in the right renal pelvis by DIP, RP and CT led us to suspect a pelvic tumor, and a right nephroureterotomy was performed. Light microscopy revealed deposits of amorphous, eosinophilic material in the pelvis and proximal portion of upper ureter, however tumor cells were not found. Electron microscopy revealed that these materials were aggregates of linear, non-branching fibrils, measuring about 8 nm in diameter. Histochemically, these were seen to be consistent with amyloid, producing an apple-orange birefringence with Congo red staining under a polarized light. Alkali Congo red staining after pretreatment of KMnO4 demonstrate that this amyloid protein was composed largely of AA protein in addition to lesser amounts of non-AA protein, and a primary localized amyloidosis (amyloid tumor) was diagnosed. A clinicopathologic study that was performed on 12 cases of primary localized amyloidosis of the pelvis, including our case, also is reported.

Amyloidosis↗
PubMed1987

Electron microscopic and cytochemical studies of the thrombocytes of the tortoise (Geoclemys reevesii).

The thrombocytes of the tortoise (Geoclemys reevesii) were studied at the electron microscopic level. The presence of a surface connected canalicular system, composed of numerous anastomosing canaliculi, has been demonstrated by the ruthenium red technique. However, monoamine storage organelles have not been found in tortoise thrombocytes. Peroxidase activity is localised to the nuclear envelope and the rough surfaced endoplasmic reticulum, but is not present in the Golgi apparatus or granules. Acid phosphatase is localised to the large inclusions with myelin bodies, but is not found in the electron-lucent small granules. These results are discussed in relation to those from comparable studies of mammalian and submammalian thrombocytes.

Acid Phosphatase↗