Biomedical subjects
Publications and source records attributed to Ji Huang.
RISBZ1 encodes the transcription factor bZIP58, which regulates grain filling; intron editing of RISBZ1 to eliminate aberrant alternatively spliced transcripts increased grain weight without compromising key agronomic traits under normal conditions, and enhanced grain weight and quality under heat stress conditions.
A novel class of benzoxaboroles was reported to induce cancer cell death but the mechanism was unknown. Using a forward genetics platform, we discovered mutations in cleavage and polyadenylation specific factor 3 (CPSF3) that reduce benzoxaborole binding and confer resistance. CPSF3 is the endonuclease responsible for pre-mRNA 3'-end processing, which is also important for RNA polymerase II transcription termination. Benzoxaboroles inhibit this endonuclease activity of CPSF3 in vitro and also curb transcriptional termination in cells, which results in the downregulation of numerous constitutively expressed genes. Furthermore, we used X-ray crystallography to demonstrate that benzoxaboroles bind to the active site of CPSF3 in a manner distinct from the other known inhibitors of CPSF3. The benzoxaborole compound impeded the growth of cancer cell lines derived from different lineages. Our results suggest benzoxaboroles may represent a promising lead as CPSF3 inhibitors for clinical development.
3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, or statins, are known to inhibit cholesterol biosynthesis and prevent inflammation and oxidative stress. To explore the effects of atorvastatin on inflammatory progression and major cardiac electrophysiological changes in myocarditis, we used an animal model of experimental autoimmune myocarditis (EAM). In this model, BALB/c mice were treated with atorvastatin and we evaluated the levels of inflammation markers and currents of ionic channels that contribute to the duration of action potential (APD) of ventricular myocytes. We demonstrated that atorvastatin treatment attenuated inflammatory infiltration and suppressed the increase in TNF-alpha and IFN-gamma levels in EAM mouse hearts. In the whole-cell patch-clamp experiment, ventricular cardiomyocyte APD was prolonged in EAM group, and atorvastatin blocked this change. We further found that atorvastatin attenuated the significant decrease in outward potassium currents in EAM myocytes. Our results suggested that atorvastatin may ameliorate EAM progression by reducing inflammatory cytokine level. Atorvastatin exerted the antiarrhythmic effects by selectively affecting cardiomyocyte ion channel activity and therefore improves myocardial repolarization.
Myocardial infarction is the leading cause of congestive heart failure and death in the industrialized world. However, the intrinsic repair mechanism of the heart is inadequate. Current therapy is limited in preventing ventricular remodeling, but can not regenerate the lost cardiomyocytes. Recent interests have been focused on cellular cardiomyoplasty which is an outside intervention to support the reparative process in the heart through transplantation of stem/progenitor cells or cardiac cells. Cellular cardiomyoplasty with stem cells is a possible option to reverse the adverse hemodynamic and neurohormonal imbalance after myocardial infarction. Experimental studies and clinical trials suggest that cellular cardiomyoplasty may benefit tissue perfusion and contractile performance of the injured heart. Although the mechanisms are still intensively debated, cellular cardiomyoplasty with stem cells has already been introduced into the clinical settings. However, it is an important challenge how stem cells are delivered to targeted area. In early studies on animals, intramyocardial injection of stem cells after thoracotomy is the predominant transplantation route which is not suitable for most patients in clinical settings. Then the catheter-based infusion of stem cells is clinically introduced and rapidly developed in patients because of the safety, convenience and mini-invasion. We mainly review the progress in catheter-based transplantation with stem cells in order to fully understand the application of various intervention-based approaches to stem cells transplantation in clinical settings.
Glucose-6-phosphate dehydrogenase is a rate-limiting enzyme of pentose phosphate pathway, existing in cytosolic and plastidic compartments of higher plants. A novel gene encoding plastidic glucose-6-phosphate dehydrogenase was isolated from rice (Oryza sativa L.) and designated OsG6PDH2 in this article. Through semiquantitative RT-PCR approach it was found that OsG6PDH2 mRNA was weakly expressed in rice leaves, stems, immature spikes or flowered spikes, and a little higher in roots. However, the expression of OsG6PDH2 in rice seedlings was significantly induced by dark treatment. The complete opening reading frame (ORF) of OsG6PDH2 was inserted into pET30a (+), and expressed in Escherichia coli strain BL21 (DE3). The enzyme activity assay of transformed bacterial cells indicated that OsG6PDH2 encoding product had a typical function of glucose-6-phosphate dehydrogenase.
Histone H3 is one of the four histones, along with H2A, H2B, and H4, which form the eukaryotic nucleosome octamer core. In this study, a new gene RH3.2A encoding an H3.2-type histone H3 protein from rice (Oryza sativa L.) was reported. RH3.2A was cloned through RT-PCR from salt-treated rice seedlings. This gene encoded a protein of 136 amino acid residues that were similar to some plant histone H3 proteins reported previously. However, the cDNA sequence of RH3.2A and other rice H3 genes were different. Alignment of RH3.2A encoding protein with other plant histone H3 proteins revealed that three amino acid residues (32, 88, and 91) were markedly different between H3.1-type and H3.2-type proteins. The mRNA expression analysis of RH3.2A revealed that RH3.2A gene was upregulated by salt stress in rice roots and ABA treatment in seedlings. The potential role of RH3.2A during salt stress was discussed.
The full-length cDNA (3612 bp) of OsNHA1 was cloned by RT-PCR approach from rice (Oryza sativa L.), which encodes a putative plasma membrane Na+/H+ antiporter. Its deduced protein, OsNHA1, has 11 transmembrane domains and a significant similarity to a plasma membrane Na+/H+ antiporter AtNHA1 from Arabidopsis thaliana. Phylogenetic analysis showed that the OsNHA1 clusters with the plasma membrane Na+/H+ antiporters from various organisms. The semi-quantitative RT-PCR assay revealed that the expression of OsNHA1 was up-regulated in both shoots and roots of rice seedlings under salt stress, whereas it was not induced in the rice seedlings treated by drought stress.
A novel C2H2-type zinc finger protein gene, ZFP 15, was cloned from rice by RT-PCR approach. The ZFP 15 gene encodes a protein of 144 amino acid residues with a predicted molecular mass of 15 kDa. The ZFP 15 protein comprises two C2H2-type zinc finger domains, a putative nuclear localization signal (NLS) at its N-terminus but the DLN-box identified in all reported plant C2H2-type zinc finger proteins was not found. A homology search revealed that ZFP 15 gene was localized within a cluster of C2H2-type zinc finger genes in BAC clone OJ1754_E06 mapped on chromosome 3. All three members in the cluster encoded proteins showed high identities in amino acids and might contribute to a co-regulation. The RT-PCR assay revealed that ZFP 15 mRNA was not regulated by cold, salt, drought and ABA stresses, though CRT/DRE and ABRE elements were found in the promoter region of ZFP 15 gene. The expression profiling also showed that ZFP 15 mRNA was expressed with a lower level in leaves and roots, but not detected in stems. Besides, ZFP15 was shown to accumulate much more in flowering spike than in immature spike. Thus, ZFP15, as the first characterized C2H2-type zinc finger protein in rice, might play a regulatory role on rice spike development.
A C2H2-type zinc finger protein gene ZFP245 was cloned by RT-PCR approach from cold treated rice seedlings. ZFP245 is 712 bp in length and encodes a 24.5 KDa protein, which has 35% identity in amino acid with SCOF-1, a cold-inducible zinc finger protein from soybean. By database search, ZFP245 was mapped on chromosome 7 and clustered together with another C2H2 zinc finger gene. Tissue expression analysis showed that ZFP245 was constitutively expressed in various rice tissues including roots, stems, leaves and spikes. The semi-quantitative-RT-PCR assay revealed ZFP245 was strongly induced after 6 h exposure to cold and drought stresses, and then reduced to the baseline. However, ZFP245 was not regulated by high salt or abscisic acid treatment. The promoter sequence of 1017 nucleotides, upstream of ZFP245, was cloned directly by PCR approach. Sequence analysis revealed a CRT/DRE element was found within the ZFP245 promoter region. Taken together, ZFP245, as the first identified C2H2-type zinc finger protein involved in stress response in monocots probably plays a role as a transcription regulator in plant cold and drought responses through an ABA-independent pathway.
The eukaryotic initiation factor 1A(eIF1A) is essential for transferring of the initiator Met-tRNA to 40S ribosomal subunits to form the 40S pre-initiation complex. In present study, we describe the cloning and characterization of two eIF1A genes from rice, which were designated as Oryza sativa eukaryotic initiation factor 1A genes OseIF1A-1, OseIF1A-2, respectively. Both rice elF1As shared high identities in amino acids with eIF1A proteins from other eukaryotes. The mRNA expression analysis revealed that OseIF1A-2 mRNA was much more accumulated than OseIF1A-1 in all tissues but each gene is expressed in root, stem, leaf and flowering spike in high and nearly equal level, and in immature spike in lower level. These results, together with their different location in unrooted phylogenetic tree inferred from amino acid sequences of all known eIF1As, suggested that there are two types of eIF1A genes with different function or different regulation in rice.
Using the cDNA of rye cytoplasmic ribosomal protein ScRPS7 as a query probe, a highly homologous rice genomic contig was obtained from Huada rice genome database. The full-length cDNA sequence of rice cytoplasmic ribosomal protein S7 was assembled by informatics based on the contig. Furthermore, with the two primers designed according to this assembled cDNA, the full-length cDNA of rice ribosomal protein was cloned by RT-PCR and named as OsRPS7. The cDNA was 919bp in length and contained a complete Open Reading Frame (ORF) of 576bp, encoding a protein of 192 amino acid residues. The deduced amino acids of OsRPS7 showed 88%,72% and 72% identity with those from Secale cereale, Arabidopsis thaliana and Brassica oleracea, respectively. The genome structure of OsRPS7 was analyzed, and its function was predicted in this paper.
Zinc finger protein is one of the important transcription factors with zinc finger domain that regulates gene expression in the eukaryotic organisms mainly by specifically interacting with target DNA sequence(cis-acting element). It could be divided into several types of zinc finger proteins, such as C2H2, C2HC, C2C2, C2HCC2C2, C2C2C2C2 etc, based on numbers and positions of Cys and His residues. Of these, C2H2 type zinc finger protein is the most clearly identified zinc finger transcription factor, with the wide existence in human, animals and plants. The characterized plant C2H2 zinc finger proteins are mainly involved in plant growth and development and the responses to environmental stresses. Up to now, more than 50 C2H2 zinc finger proteins have been reported in plants including petunia, Arabidopsis, wheat and rice, and most of them have the plant-specific QALGGH motif in zinc finger domain. This paper briefly introduces the structure, recognition of target-DNA sequence and functions involved in development or environmental stresses of plant C2H2 zinc finger proteins.
The pentose phosphate pathway (PPP) is the important metabolism pathway in plant. In the present study, a cDNA encoding one of the key enzymes of PPP, 6-phosphogluconate dehydrogenase(6PGDH), was isolated from rice and designated as Os6PGDH. The Os6PGDH encoding protein is a cytosolic isoenzyme according to the absence of plastid transit peptide at the N-terminus. The full-length cDNA of 1751 bp encodes 480 amino acids and its putative protein sequence is 94%, 84% and 83% identical to maize, spinach and alfalfa 6PGDHs respectively. Comparison of the cloned mRNA sequence with that of the genomic sequence from the Rice Genome Project showed a simple genomic organization devoid of introns in the translated region of the gene. RT-PCR experiments revealed that Os6PGDH expression was high in inflorescence, low in root and embryos but almost absent in leaves. Furthermore, Os6PGDH was up-regulated in the shoots under salt stress. It is suggested that 6PGDH in plant may play an important role in cell division and salt response.
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In silico cloning was a new strategy of gene cloning developed with the development of genome, EST projects and bioinformatics. Using wheat glucose-6-phosphate dehydrogenase cDNA (clone: Tagpdl) sequence as a querying probe, one highly homologous BAC clone sequence was obtained from rice sequence database of GenBank and the putative cDNA sequence of rice glucose-6-phosphate dehydrogenase was assembled according to the wheat clone. Furthermore, the full-length cDNA of rice glucose-6-phosphate dehydrogenase was cloned by RT-PCR with two primers designed based on this assembled cDNA sequence. Since this fragment contained a complete ORF of 1515 bp with a stop codon in its upstream and poly(A) signal in its downstream, it could be concluded that a full-length gene (GenBank accession number AY078072), which was named as OsG6PDH. Homology analysis of OsG6PDH showed a 88% identity with wheat and the deduced amino acid showed 89%, 79% and 80% homology with G6PDH from wheat, tomato and tobacco respectively. OsG6PDH was expressed in inflorescence, embryo, root and leaf of rice, with a slightly higher in inflorescence and root. It was also discussed in this paper that the application of in silico cloning in the isolation of functional genes from rice.
Serial analysis of gene expression (SAGE) is recently developed, a sequenced-based technique, which permits comprehensive and quantitative gene expression profiles from specific tissues or cells. SAGE has been successfully applied for transcriptome research and identification of differentially expressed genes between mRNA populations. This article mainly reviews the principle,development and application of SAGE.