Biomedical subjects

Shin-ichiro Nishimatsu

Publications and source records attributed to Shin-ichiro Nishimatsu.

3 recordsLinked to original sources

PubMed2004

Bone morphogenetic protein-3 family members and their biological functions.

Bone morphogenetic protein-3 and 3b (BMP-3 and BMP-3b) together represent a unique subgroup of the BMP family. BMP-3b shares 82% amino acid identity with BMP-3 in the mature region (ligand domain), but only 37% in the pro-region (pro-domain). In osteoblasts, BMP-3 and 3b have similar antagonistic activity against BMP-2, but they are differentially regulated. In developing embryos, BMP-3 and 3b have different dorsalizing activities. BMP-3b triggers secondary head formation in an autonomous manner, whereas BMP-3 induces aberrant tail formation. Loss-of-function analysis demonstrates that coordinated activity of xBMP-3b and cerberus, a head inducer, are required for head formation in Xenopus embryos. At the molecular level, BMP-3b antagonizes both nodal-like proteins (Xnr1 and derriere) and ventralizing BMPs (BMP-2 and ADMP), whereas BMP-3 only antagonizes ventralizing BMPs. Moreover, BMP-3b, but not BMP-3, associates with the monomeric form of Xnr1, a nodal-like protein. These molecular features of BMP-3 and 3b are due to their distinct pro-regions. These findings suggest that the processing of precursor regions and assembly of BMP-3 and 3b are important in various developmental processes and organogenesis.

Animals↗

PubMed2003

Coordination of BMP-3b and cerberus is required for head formation of Xenopus embryos.

Bone morphogenetic proteins (BMPs) and their antagonists are involved in the axial patterning of vertebrate embryos. We report that both BMP-3b and BMP-3 dorsalize Xenopus embryos, but act as dissimilar antagonists within the BMP family. BMP-3b injected into Xenopus embryos triggered secondary head formation in an autonomous manner, whereas BMP-3 induced aberrant tail formation. At the molecular level, BMP-3b antagonized nodal-like proteins and ventralizing BMPs, whereas BMP-3 antagonized only the latter. These differences are due to divergence of their pro-domains. Less BMP-3b than BMP-3 precursor is proteolytically processed in embryos. BMP-3b protein associated with a monomeric form of Xnrl, a nodal-like protein, whereas BMP-3 did not. These molecular features are consistent with their expression profiles during Xenopus development. XBMP-3b is expressed in the prechordal plate, while xBMP-3 is expressed in the notochord. Using antisense morpholino oligonucleotides, we found that the depletion of both xBMP-3b and cerberus, a head inducer, caused headless Xenopus embryos, whereas the depletion of both xBMP-3 and cerberus affected the size of the somite. These results revealed that xBMP-3b and cerberus are essential for head formation regulated by the Spemann organizer, and that xBMP-3b and perhaps xBMP-3 are involved in the axial patterning of Xenopus embryos.

Amino Acid Sequence↗

PubMed2002

Paraquat-induced gene expression in rat lung tissues using a differential display reverse transcription-polymerase chain reaction.

Increased formation of reactive oxygen species is a cause of paraquat (PQ)-induced injury and also provides a link between the signaling pathways and transcriptional events that regulate the expression of a large number of genes. However, the molecular mechanisms involved in PQ-induced injury remain unclear. To investigate the changes in gene expression at the onset of PQ injury, we used the differential display-polymerase chain reaction (PCR) method. Rats were treated intraperitoneally with 20 mg/kg PQ, and after 3 h the lungs were immediately excised. Samples of mRNA from normal and treated rats were used to prepare radiolabeled cDNAs, which were electrophoresed. Then the transcription levels were compared. We isolated 26 fragments of cDNA that were potentially affected by PQ, and determined their nucleotide sequences. Six clones of interest were selected and analyzed further. The reverse transcript-PCR based on their sequence information confirmed the differential expression for five clones: four clones were up-regulated and one was down-regulated. We were particularly interested in two genes that had homology with the known gene: TATA box-binding protein-associated factor, RNA polymerase II, B, 150 kDa (TAFIIB), and a candidate gene for lipodystrophy, Lpin2. Both genes were significantly up-regulated within 3 h of PQ intake and the stimulation continued during our 24-h observation period. In addition, up-regulation of Lpin2 was observed in the lungs, but not in the liver and kidneys. In situ hybridization using lung sections showed that the expression of both genes was strongly visualized in Clara cells and in alveolar macrophages. These findings suggest a stimulation of transcription levels and changes in lipid metabolism in Clara cells and in macrophages in the lungs, which result in their playing a crucial role at the onset of PQ-driven pulmonary injury.

Animals↗