Transcription factor is one of the key factors in the regulation of gene expression at the transcriptional level. It plays an important role in plant growth, active components biosynthesis and response to environmental change. This paper summarized the structure and classification of bHLH transcription factors and elaborated the research progress of bHLH transcription factors which regulate the active components in plants, such as flavonoids, alkaloids, and terpenoids. In addition, the possibility of increasing the concentration of active substances by bHLH in medicinal plants was assessed. The paper emphasized great significance of model plants and multidisciplinary research fields including modern genomics, transcriptomics, metabolomics and bioinformatics, providing the contribution to improve the discovery and function characterization of bHLH transcription factors. Accelerating the research in the mechanism of bHLH transcription factors on the regulation of active components biosynthesis will promote the development of breeding and variety improvement of Chinese medicinal materials, also ease the pressure of resources exhaustion of traditional Chinese medicine home and abroad.
Alkaloids ; biosynthesis ; Basic Helix-Loop-Helix Transcription Factors ; chemistry ; classification ; genetics ; metabolism ; Flavonoids ; biosynthesis ; Plants, Medicinal ; genetics ; metabolism ; Terpenes ; metabolism

Iron is one of the essential mineral micronutrients for plants. Low concentrations of effective iron in soil can easily increase risk of plant iron deficiency. Several members of bHLH transcription factors family participate in the response to iron deficiency and play an important role in iron regulation of plants. In order to better understand the mechanism of iron deficiency response, an overview of the structure, classification, function and regulatory mechanism of bHLH transcription factors was given in this review as well as signaling pathway triggered by iron deficiency. It will provide theoretical basis and design strategies for cultivating iron deficiency tolerant or iron-rich crops using bHLH transcription factors.
Arabidopsis ; genetics ; metabolism ; Basic Helix-Loop-Helix Transcription Factors ; genetics ; metabolism ; Gene Expression Regulation, Plant ; Iron ; deficiency ; Signal Transduction ; physiology

The expression levels of hypoxia-inducible factor 1alpha (HIF-1α) and HIF-2α in pancreatic cancer (PC) and their association with clinicopathologic characteristics were investigated in order to elucidate their roles in the development of PC. HIF-1α and HIF-2α mRNA levels in 20 patients with PC were detected by quantitative real-time polymerase chain reaction. The expression of HIF-1α and HIF-2α protein in samples from other 90 patients with PC was measured by immunohistochemistry. Correlations between the expression of HIF-1α or HIF-2α and clinicopathologica features and prognosis were analyzed. The expression of both HIF-1α and HIF-2α mRNA was up-regulated in most cancer tissues (P<0.05). HIF-1α staining was weakly positive in most cancer tissues and strongly positive in adjacent pancreas tissues (P<0.05). Clinicopathologic analysis revealed that relatively strong HIF-1α expression in cancer tissues was related to greater invasion (P<0.05), higher tumor pathologic stage (P<0.05), higher American Joint Committee on Cancer (AJCC) stage (P<0.05) and shorter overall survival time (P<0.05). Conversely, HIF-2α staining was strongly positive in most cancer tissues and weakly positive in adjacent pancreas tissues. Clinicopathologic analysis revealed that relatively strong HIF-2α expression in cancer tissues was related to less invasion (P<0.05), lower tumor pathologic stage (P<0.05), lower AJCC stage (P<0.05) and longer overall survival time (P<0.05). Moreover, the HIF-1α(high)/HIF-2α(low) group showed a shorter survival time than the HIF-1α(low)/HIF-2α(high) group. In conclusion, although HIF-1α and HIF-2α mRNA expression patterns are the same, their protein expression patterns are significantly different and they play different roles in PC. Combined analysis of HIF-1α and HIF-2α expression might be useful to predict the prognosis of patients with PC.
Basic Helix-Loop-Helix Transcription Factors ; genetics ; metabolism ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; metabolism ; Pancreatic Neoplasms ; metabolism ; pathology ; Prognosis ; RNA, Messenger ; genetics

Energy metabolism plays an important role in life survival for species living in high altitude hypoxia condition. Air-breathing organisms require oxygen to create energy. Tibetans are the well-adapted highlanders in Qinghai-Tibetan Plateau. It was thought that different metabolic approaches could lead to different adaptation traits to high altitude hypoxia. Recently identified hypoxia inducible factors pathway regulators, endothelial PAS domain protein1 (EPAS1)/HIF-2a and PPARA, were involved in decreasing hemoglobin concentrations in Tibetans. Because EPAS1 and PPARA also modulated the energy metabolism during hypoxia, we hypothesized that positive selected EPAS1 and PPARA genes were also involved in unique energy metabolisms in Tibetans. In this brief review, we take a look into genetic determinations to energy metabolisms for hypoxia adaptations traits in Tibetans and mal-adaptive conditions such as high altitude diseases.
Acclimatization ; genetics ; Altitude ; Basic Helix-Loop-Helix Transcription Factors ; metabolism ; Energy Metabolism ; Hemoglobins ; analysis ; Humans ; Hypoxia ; metabolism ; Oxygen ; metabolism ; Phenotype ; Tibet

OBJECTIVETo investigate the expression and mutation of Mad1, Mxi1 and Rox genes in leukemia cells.

METHODSExpression and mutation of Mad1, Mxi1 and Rox genes in bone marrow mononuclear cells (BMMNC) from 26 de novo acute leukemia (AL) patients, and in peripheral blood mononuclear cells (PBMNC) from 30 healthy volunteers, as well as in 7 human leukemic cell lines were analyzed by reverse transcription-polymerase chain reaction (RT-PCR), single strand conformational polymorphism (SSCP) and DNA sequencing.

RESULTSRT-PCR showed that all the above cells expressed Mad1, Mxi1 and Rox mRNA. SSCP revealed four polymorphisms: two in Mad1, one each in Mxi1 and Rox. DNA sequencing detected nine missense mutations: two in Mad1 in AL patients, four in Mxi1 (three in AL patients and one in KG-1 cell line), and three in Rox in AL patients. The mutations of Mad1, Mxi1 and Rox mRNA were detected in 2, 3 and 3 patients, respectively.

CONCLUSIONIt is for the first time to demonstrate the mutations of Mad1, Mxi1 and Rox genes in AL patients suggesting these mutated genes involve in the pathogenesis of leukemia.

Adolescent ; Adult ; Aged ; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors ; genetics ; metabolism ; Basic Helix-Loop-Helix Transcription Factors ; genetics ; metabolism ; Cell Cycle Proteins ; genetics ; metabolism ; Female ; Humans ; Leukemia ; genetics ; metabolism ; Male ; Middle Aged ; Mutation ; Nuclear Proteins ; genetics ; metabolism ; Polymorphism, Single-Stranded Conformational ; Repressor Proteins ; genetics ; metabolism ; Tumor Suppressor Proteins ; genetics ; metabolism

To clarify the function and molecular mechanism of miR-155 in myogenic differentiation of C2C12, we constructed adenovirus over-expression vector of miR-155, then C2C12 cells were infected by adenovirus and induced myogenic differentiation. First, we observed the morphology of C2C12 after differentiation. Then the mRNA and protein expressions of myogenic markers (MyoD, MyoG and MyHC) were detected by qPCR and western blotting. Subsequently, the dual luciferase reporter gene assay was carried out to validate putative target gene (TCF4) of miR-155. Meanwhile, mRNA level of TCF4 was analyzed after over-expressing miR-155. The results show that over-expressed miR-155 reduced myotubes formation. Moreover, the mRNA and protein expression of MyoG and MyHC decreased significantly (P < 0.01). Further research demonstrated miR-155 bound the one (4532-4538) of three putative sites (1487-1493,1516-1522, 4532-4583) of TCF4 by luciferase reporter gene assay and the mRNA level of TCF4 decreased notably (P < 0.05). The data suggest that miR-155 inhibited myogenic differentiation of C2C12 through targeted TCF4.
Animals ; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors ; genetics ; Cell Differentiation ; Cell Line ; Genetic Vectors ; Mice ; MicroRNAs ; genetics ; Myoblasts ; cytology ; Myogenin ; genetics ; metabolism ; Myosin Heavy Chains ; genetics ; metabolism ; RNA, Messenger ; genetics ; Transcription Factor 4

OBJECTIVETo detect the expression of Math1, Hes1 and Hes5 in greater epithelial ridge (GER) cells of rat cochlear and explore their influence on hair cell differentiation.

METHODSPostnatal day 0 (P0), day 1 (P1) , day 3 (P3) day 4 (P4) and day 5 (P5) rat cochlear were dissected respectively and then pure GER cells were separated by a combinatorial approach of attachment and mechanical separation. The total RNA of GER cells was extracted by Trizol one step method and the expression of Math1, Hes1 and Hes5 in GER cells was detected with reverse transcription polymerase chain reaction.

RESULTSMath1 was expressed in P0 - P5 rat GER cells and Hes1 was expressed only in PO - P3 rat GER cells, while there was no expression of Hes5 in P0 - P5 rat GER cells.

CONCLUSIONSProbably only when the expression of Math1 reaches a certain level can it induce GER cells to differentiate into hair cells. Meanwhile this process might controlled by Hes1 to some extent.

Animals ; Basic Helix-Loop-Helix Transcription Factors ; genetics ; metabolism ; Cell Differentiation ; Cochlea ; cytology ; metabolism ; Epithelial Cells ; metabolism ; Gene Expression Regulation, Developmental ; Hair Cells, Auditory ; cytology ; metabolism ; Homeodomain Proteins ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Transcription Factor HES-1

OBJECTIVETo construct the eukaryotic expression plasmid of mouse histone lysine methyltransferase Setd7 and detect its effect on neuron development.

METHODSThe clone of mouse Setd7 was obtained and inserted into the eukaryotic expression vector pCMV-3tag-6-Flag. The plasmid was transfected into HEK 293T and identified by Western blot. Real-time PCR was used to detect the effect of Setd7 on the neuron differentiation marker gene Ngn 1 mRNA expression. Dual luciferase reporter system was used to detect the effect of Setd7 on Ngn 1 mRNA expression. Real-time PCR was used to detect the effect of Setd 7 siRNA plasmid on Ngn 1 mRNA expression.

RESULTSAn eukaryotic expression plasmid of Setd 7 was successfully constructed. Setd7 induced Ngn 1 mRNA expression and increased Ngn 1 promoter activity. Also, the knockdown of Setd 7 inhibited Ngn 1 mRNA expression.

CONCLUSIONHistone lysine methyltransferase Setd7 can enhance neuron differentiation marker gene Ngn 1 transcription.

Animals ; Basic Helix-Loop-Helix Transcription Factors ; genetics ; metabolism ; Gene Expression Regulation ; Genetic Vectors ; HEK293 Cells ; Histone-Lysine N-Methyltransferase ; genetics ; metabolism ; Humans ; Mice ; Nerve Tissue Proteins ; genetics ; metabolism ; Protein Methyltransferases ; genetics ; metabolism ; RNA, Messenger ; genetics ; Transfection

OBJECTIVETo construct an eukaryotic expression vector for miRNA-1-2 that can be expressed in rat H9C2 cardiomyocytes.

METHODSThe precursor miRNA (pre-miRNA) DNA template for miRNA-1-2 was designed and generated by PCR amplification. The DNA template was inserted into the hairpin RNA expression vector pSilence-4.1-neo and identified by DNA sequencing analysis. The recombinant plasmid DNA was then transfected into H9C2 cells via Lipofectamine, and the green fluorescence protein expression vector pEGFP-N3 served as the transfection marker. Twenty-four hours after transfection, the total cellular RNA was extracted using TRIzol reagent, and thermoscript reverse transcriptase (RT)-PCR was performed to determine miRNA-1-2 precursor expression.

RESULTS AND CONCLUSIONDNA sequencing indicated that the miR-1-2 expression plasmid was correctly constructed. The precursor miRNA-1-2 was successfully expressed in the H9C2 cells, and the expression of Hand2 protein could be efficiently inhibited by miRNA-1.

Animals ; Basic Helix-Loop-Helix Transcription Factors ; genetics ; metabolism ; Cell Line ; Down-Regulation ; Green Fluorescent Proteins ; genetics ; metabolism ; MicroRNAs ; genetics ; Myocytes, Cardiac ; cytology ; metabolism ; Plasmids ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; RNA, Small Interfering ; genetics ; Rats ; Transfection

OBJECTIVETo observe the effect of activation of Notch1 signaling pathway by Notch intracellular domain (NICD) plasmid transfection on pancreatic cancer cell proliferation and explore the underlying mechanism.

METHODSThe transfection rates were observed under microscope with fluorescence stimulation, and mRNA expression levels of Hes1 were detected by real-time PCR. Cell proliferation changes were evaluated by CCK-8 after NICD and control plasmid transfection in pancreatic cancer cells. Caspase 3 activity was examined using a caspase 3 detection kit.

RESULTSThe transfection rates of NICD plasmid were up to 80% by fluorescence stimulation observation. Hes1 expression was significantly increased after NICD plasmid transfection, suggesting the activation of Notch1 signaling pathway. NICD plasmid transfection significantly promoted cancer cell proliferation compared to control plasmid transfeciton. The activities of caspase 3 were obviously decreased after NICD plasmid transfection in 3 pancreatic cancer cell lines.

CONCLUSIONActivation of Notch1 signaling pathway by NICD plasmid transfection can promote the proliferation of pancreatic cancer cells by inhibiting the apoptosis pathway.

Apoptosis ; Basic Helix-Loop-Helix Transcription Factors ; metabolism ; Caspase 3 ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; Homeodomain Proteins ; metabolism ; Humans ; Pancreatic Neoplasms ; metabolism ; pathology ; Plasmids ; Receptor, Notch1 ; genetics ; metabolism ; Signal Transduction ; Transcription Factor HES-1 ; Transfection