Biomedical subjects

Shuji Hirata

Publications and source records attributed to Shuji Hirata.

21 records · Page 2Linked to original sources

PubMed2002

Novel isoforms of the mRNA for human female sex steroid hormone receptors.

In our recent reports, the novel isoform cDNAs of the ER alpha (ER alpha isoform S cDNA), ER beta (ER beta isoform M cDNA) and PR (PR isoform S and PR isoform T cDNAs) have been identified. These isoform cDNAs contained the previously unidentified 5'-sequences on exons 4-8 (ER alpha isoform S cDNA), exons 5-8 (ER beta isoform M cDNA) or exons 4-8 (PR isoform S and PR isoform T cDNAs). The genomic DNA analysis revealed that the 5'-sequences were derived from the novel independent exons, the ER alpha exon S, ER beta exon M, PR exon S and PR exon T, respectively. Furthermore, the existence of the novel variant mRNA, termed the i45 PR mRNA variant, with the insertion of the previously unidentified exons, termed the exons i45a and i45b, has been demonstrated by the reverse transcription-polymerase chain reaction on the RNA of the human uterine endometrium. From these results, we have concluded that the genes for the human female sex steroid hormone receptors contain the novel intronic exons, that the novel isoform mRNAs are transcribed using the intronic exon and exons 4-8 (or exons 5-8) of the gene, and that the novel variant mRNA is generated by the insertion of the intronic exons in the PR. In the present communication, our recent data along with others on the novel isoform/variant mRNAs for the human female sex steroid hormone receptors will be summarized.

5' Untranslated Regions↗

PubMed2002

Progesterone receptor mRNA variant containing novel exon insertions between exon 4 and exon 5 in human uterine endometrium.

The presence of human progesterone receptor (PR) mRNA variants has been demonstrated in uterine endometrium and breast tissues as well as in cancer cells of these tissues. While exon deletions by the alternative splicing in these variants have been reported, there are few reports available on the PR mRNA variants with exon insertion. In the present study, we attempted to detect a PR mRNA variant containing the exon insertions in normal uterine endometrium. Endometrial tissues were subjected to reverse transcription-polymerase chain reaction (RT-PCR) with PCR primers which were located in exons 3 and 8. Analysis of the RT-PCR products revealed the presence of a novel PR mRNA variant which contained a 232 bp inserted nucleotide sequence between exons 4 and 5. We termed this transcript the "i45 PR mRNA variant". Genomic analysis indicated that the inserted sequence was derived from two novel independent exons of 123 bp and 109 bp, termed "exon i45a" and "exon i45b", respectively, which are located between exons 4 and 5 of the human PR gene. The i45 PR mRNA variant was further detected in uterine endometrial cancer tissues as well as in the normal uterine endometrium. These results demonstrate the presence of a novel PR mRNA variant with exon insertions in the human tissue for the first time. The i45 PR variant protein, possibly transcribed from this i45 PR mRNA variant, may play physiological and/or pathological roles in the human uterine endometrium.

Base Sequence↗

PubMed2002

Relationship between sperm mitochondrial membrane potential, sperm motility, and fertility potential.

AIM: To analyze the relationship between sperm mitochondrial membrane potential and sperm motility parameters by means of a computer-assisted sperm analyzer (CASA) and in-vitro fertilization rate(%FR). METHODS: Semen samples were obtained from 26 men undergoing in vitro fertilization-embryo transfer (IVF-ET). Informed consent was obtained from all men prior to the study. Samples were prepared using wash and swim-up method in HEPES-HTF medium. The sperm motility (%MOT), progressive motility (%PMOT), average path velocity (VAP) microm/s), straight line velocity (VSL) (micro m/s), curvilinear velocity (VCL) (microm/s) and %hyperactivated sperm (%HA), and the %FR were assessed. The samples were incubated in the presence of 2.0 mciromol/L of 5,5',6,6'-tetra-chloro-1,1',3,3'-tetraethylbenzimidazolyl-carbocyanine iodide (JC-1) for 30 min at 37 degrees C in air and washed in PBS before flow cytometry (FACSCalibur: Becton Dickinson) analysis. The mitochondrial probe JC-1 was used to identify the mitochondrial membrane potential. The sperm was divided into three populations according to the fluorescence pattern as follows: the high mitochondrial membrane potential group (n=8), the moderate group (n=5), and the low group (n=13). Statistical analysis was performed using unpaired t-test. RESULTS: Significant differences were found between the high and the low groups in %MOT (91.1+/-8.5 vs 63.0+/-32.7, mean+/-SD), VAP (73.0+/-14.2 vs 52.1+/-12.5), VCL (127.0+/-28.1 vs 87.0+/-22.6), %HA (27.3+/-23.6 vs 7.2+/-9.0) and %FR [73.2 (48/56) vs 59.0 (69/117)]. No significant differences were found in other CASA parameters. CONCLUSION: When the sperm mitochondrial membrane potential increases, sperm motility parameters and fertility potential will also increase. The JC-1 dye method is useful to predict sperm fertility potential.

Embryo Transfer↗