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 protein encoded by gene Nhlh2 (nescient helix-loop-helix 2, also known as HEN2 or NSCL2) is a new member of basic helix-loop-helix (bHLH) transcription factor family and is specifically expressed in nervous system, especially in neuroendocrine tissue. The homologous genes of Nhlh2 have been found in many eukaryotic organisms such as chicken, mouse, rat, cattle, and human. The functional researches of Nhlh2 are mainly focused on neuroendocrine system, retina development, and tumors. Some preliminary results have been obtained in the investigation of molecular regulation mechanism. This article summarizes the recent research advances in Nhlh2.
Animals ; Basic Helix-Loop-Helix Transcription Factors ; biosynthesis ; physiology ; Humans ; Neoplasms ; metabolism ; Nervous System ; metabolism ; Neurosecretory Systems ; metabolism ; Retina ; growth & development ; metabolism ; Species Specificity

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

Objective To observe the skin ultrastructure change of electric shock death rats and to test the expression changes of hypoxia-inducible factor-2α （HIF-2α） and heart type-fatty acid-binding protein （H-FABP） of myocardial cells, in order to provide basis for forensic identification of electric shock death. Methods The electric shock model of rats was established. The 72 rats were randomly divided into control group, electric shock death group and postmortem electric shock group. Each group was divided into three subgroups, immediate （0 min）, 30 min and 60 min after death. The skin changes of rats were observed by HE staining, the changes of skin ultrastructure were observed by scanning electron microscopy, and the expression of HIF-2α and H-FABP in rats myocardium was tested by immunohistochemical staining. Results The skin in the electric shock death group and postmortem electric shock group had no significant difference through the naked eye or by HE staining. Under the scanning electron microscope, a large number of cellular debris, cells with unclear boundaries, withered cracks, circular or elliptical holes scattered on the cell surface and irregular edges were observed. A large number of spherical foreign body particles were observed. Compared with the control group, the expression of HIF-2α in all electric shock death subgroups increased, reaching the peak immediately after death. In the postmortem electric shock group, HIF-2α expression only increased immediately after death, but was lower than that of electric shock death group （P<0.05）. Compared with the control group, the expression of H-FABP in all subgroups of electric shock death group and postmortem electric shock group significantly decreased. The expression of H-FABP in all subgroups of electric shock death group was lower than that of the postmortem electric shock group （P<0.05）. Conclusion Electric shock can increase HIF-2α expression and decrease H-FABP expression in the myocardium, which may be of forensic significance for the determination of electric shock death and identification of antemortem and postmortem electric shock.
Animals ; Autopsy ; Basic Helix-Loop-Helix Transcription Factors/metabolism* ; Fatty Acid Binding Protein 3/metabolism* ; Myocardium/metabolism* ; Myocytes, Cardiac/metabolism* ; Rats ; Skin/ultrastructure*

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

OBJECTIVE: To investigate the expression of hypoxia inducible factor 2α (HIF-2α) in every clinical stage and the pathological grade of epithelial ovarian cancer, and to discuss the role of HIF-2α in carcinogenesis, progression and outcomes of epithelial ovarian tumors. METHODS: Protein expression of HIF-2α in epithelial ovarian tissue from 77 randomly selected specimens was detected by SP immunohistochemistry staining. The relation between the expression of HIF-2α and prognosis of 40 patients with epithelial ovarian cancer was analyzed by Cox regression model. RESULTS: There was positive relation between the positivity rates of HIF-2α and malignant grade, FIGO stage, histological grade and invasive metastasis. The live time of the patients with HIF-2α positive expression was shorter than those with negative expression. CONCLUSION HIF-2α may play an important role in the genesis, development, invasion and metastasis of ovarian cancer and it may possess the vital clinical significance for prognosis evaluation.
Basic Helix-Loop-Helix Transcription Factors ; metabolism ; Carcinoma, Ovarian Epithelial ; Disease Progression ; Female ; Humans ; Immunohistochemistry ; Neoplasms, Glandular and Epithelial ; diagnosis ; metabolism ; Ovarian Neoplasms ; diagnosis ; metabolism ; Prognosis

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

OBJECTIVE: To determine the time course and potential mechanism of fibroblast growth factor-1 (FGF-1) in the regulation of adipogenesis.
 METHODS: We cultured human Simpson-Golabi-Behmel syndrome (SGBS) pre-adipocytes with recombinant FGF-1 and harvested cells at various stages prior to and during differentiation; at cell proliferation (D-3), confluence (D0), early (D3), middle (D7) and mature (D14) stages of differentiation. We determined lipid accumulation in mature adipocytes by morphological observation and quantitative measurement of oil red O staining. We also examined the expression of adipogenic genes and related markers involved in the Wnt/β-catenin pathway using quantitative Real-time PCR and Western blot.
 RESULTS: Compared to control SGBS cells, treatment with FGF-1 increased lipid accumulation; induced a sustained increase in the mRNA for peroxisome proliferater-activated receptor γ (PPARγ), glyceraldehyde-3-phosphate dehydrogenase (G3PDH), adiponectin and glucose transporter type 4 (GLUT4); and promoted a sustained decrease in expression of markers of the Wnt/β-catenin pathway, β-catenin and transcription factor 4 (TCF4).
 CONCLUSION The adipogenic effects of FGF-1 are apparent throughout the whole priming and differentiation period in human SGBS pre-adipocytes. Furthermore, our results suggest that FGF-1 
promotes adipogenesis, at least in part, via a sustained decrease in activity of the Wnt/β-catenin pathway.
Adipocytes ; drug effects ; metabolism ; Adipogenesis ; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors ; metabolism ; Cell Differentiation ; Cells, Cultured ; Fibroblast Growth Factor 1 ; pharmacology ; Humans ; Recombinant Proteins ; pharmacology ; Transcription Factor 4 ; Transcription Factors ; metabolism ; Wnt Signaling Pathway ; beta Catenin ; metabolism

OBJECTIVETo study the effect of Yishen Daluo Decoction (YDD) on the expression of protein lipoprotein (PLP), oligodendrocyte transcription factor 1 (Olig 1), and oligodendrocyte transcription factor 2 (Olig2) in mice with experimental autoimmune encephalomyelitis (EAE).

METHODSTotally 40 mice were randomly divided into 4 groups, i.e., the normal group, the model group, the Chinese medicine (CM) group, and the Western medicine (WM) group, 10 mice in each group. Each mouse in the model, CM, and WM groups was subcutaneously injected with 200 microL antigen emulsion (containing 150 micro g PLP139 -151 and 400 micro g H37RA) in two parts at the upper abdomen on the first day. 100 microLBordetella pertussis juice (containing 0. 6 x 10(6) Bordetella pertussis) was injected by caudal vein on the first and the third day. On the 7th day after modeling, each mouse in the normal group and the model group was intragastrically given normal saline (0. 1 mL/10 g). YDD (0. 2 g crude drug/10 g) was intragastrically given to mice in the CM group, and prednisone (0. 039 mg/10 g) was intragastrically given to mice in the WM group. All mice were intervened for 54 days. Changes of PLP, Olig1, and Olig2 in the brain tissue of EAE mice were detected by Western blot. Results The levels of PLP and Olig2 in the brain tissue of the model group were less than those of the normal group (P <0.05). Compared with the model group, the levels of PLP, Olig1, and Olig2 in the brain tissue increased in the CM group (P <0.05); the levels of PLP and Olig2 in the brain tissue increased in the WM group (P <0.05). Compared with the WM group, the level of Olig1 in the brain tissue increased in the CM group (P <0.05).

CONCLUSIONYDD could enhance remyelination by elevating the levels of Olig1 and Olig2 in the brain tissue of EAE mice.

Animals ; Basic Helix-Loop-Helix Transcription Factors ; metabolism ; Brain ; Drugs, Chinese Herbal ; pharmacology ; Encephalomyelitis, Autoimmune, Experimental ; metabolism ; Gene Expression ; Mice ; Nerve Tissue Proteins ; metabolism ; Oligodendrocyte Transcription Factor 2 ; Transcription Factors