Resolving a nearly 90-year-old enigma: The rare Fagus chienii is conspecific with F. hayatae based on molecular and morphological evidence.

Taxonomic uncertainties of rare species often hinder effective prioritization for conservation. One such taxonomic uncertainty is the 90-year-old enigma of Fagus chienii. F. chienii was previously only known from the type specimens collected in 1935 in Pingwu County of Sichuan Province, China, and has long been thought to be on the verge of extinction. However, morphological similarities to closely related Fagus species have led many to question the taxonomic status of F. chienii. To clarify this taxonomic uncertainty, we used the newly collected samples to reconstruct a molecular phylogeny of Chinese Fagus species against the phylogenetic backbone of the whole genus using seven nuclear genes. In addition, we examined nine morphological characters to determine whether F. chienii is morphologically distinct from its putatively closest relatives (F. hayatae, F.longipetiolata, and F.lucida). Both morphological and phylogenetic analyses indicated that F. chienii is conspecific with F. hayatae. We recommended that F. chienii should not be treated as a separate species in conservation management. However, conservation strategies such as in situ protection and ex situ germplasm preservation should be adopted to prevent the peculiar "F. chienii" population from extinction.

MicroRNA-378 Suppressed Osteogenesis of MSCs and Impaired Bone Formation via Inactivating Wnt/ß-Catenin Signaling.

MicroRNAs (miRNAs) have been reported to serve as silencers to repress gene expression at post-transcriptional levels. Multiple miRNAs have been demonstrated to play important roles in osteogenesis. MicroRNA (miR)-378, a conserved miRNA, was reported to mediate bone metabolism and influence bone development, but the detailed function and underlying mechanism remain obscure. In this study, the miR-378 transgenic (TG) mouse was developed to study the role of miR-378 in osteogenic differentiation as well as bone formation. The abnormal bone tissues and impaired bone quality were displayed in the miR-378 TG mice, and a delayed healing effect was observed during bone fracture of the miR-378 TG mice. The osteogenic differentiation of mesenchymal stem cells (MSCs) derived from this TG mouse was also inhibited. We also found that miR-378 mimics suppressed, whereas anti-miR-378 promoted osteogenesis of human MSCs. Two Wnt family members, Wnt6 and Wnt10a, were identified as bona fide targets of miR-378, and their expression was decreased by this miRNA, which eventually induced the inactivation of Wnt/ß-catenin signaling. Finally, the short hairpin (sh)-miR-378-modified MSCs were locally injected into the fracture sites in an established mouse fracture model. The results indicated that miR-378 inhibitor therapy could promote bone formation and stimulate the healing process in vivo. In conclusion, miR-378 suppressed osteogenesis and bone formation via inactivating Wnt/ß-catenin signaling, suggesting that miR-378 may be a potential therapeutic target for bone diseases.

Evaluation of genetic susceptibility loci for chronic hepatitis B in Chinese: two independent case-control studies.

BACKGROUND: A recent genome-wide scan has identified two genetic variants in the HLA-DP region strongly associated with hepatitis B infection in Japanese. This study evaluates the effects of these risk variants in Chinese, where the HBV infection is the most popular in the world. METHODS AND FINDINGS: We have assessed the relationship between these two single nucleotide polymorphisms (rs3077 and rs9277535) and chronic hepatitis B infection in two independent case-control studies. The first population in Chinese Han included 736 patients and 782 spontaneously recovered controls. The second set was established in Chinese Zhuang minority of 177 patients and 208 controls. Both A alleles of rs3077 and rs9277535 significantly deceased the risk to CHB in Chinese Han (OR = 0.540, 95%CI: 0.464-0.628, P = 4.068×10(-16) and OR = 0.696, 95%CI: 0.601-0.806, P = 1.062×10(-6), respectively). Conceivably, rs9277535 was found to be associated with decreased risk of the disease in Chinese Zhuang, with an OR of 0.606 (95%CI, 0.441-0.833, P = 0.002). CONCLUSION: Chronic hepatitis B susceptibility loci in HLA-DP region (rs3077 and rs9277535) identified by genome-wide scan in Japanese population were validated in Chinese population. These findings might provide clues to develop screening and surveillance strategies.

[The ubiquitin-proteasome proteolytic pathway and tumorigenesis].

The ubiquitin-proteasome proteolytic pathway, a major pathway for protein degradation in cells, plays a critical role in the protein metabolism. So abnormality of the ubiquitin-proteasome proteolytic pathway is closely related to many diseases, especially cancer. In this paper, we reviewed the study of the significant role of the ubiquitin-proteasome proteolytic pathways during the cell cycle, DNA repair and apoptosis, especially the relationship between these pathways and tumorigenesis.

[Chicken genome project and its application in genetic research].

Chicken is an important model organism for studying all sorts of biological problems due to its unique biological features. Two strains of chicken, the egg-laying layer and meat-producing broiler, which were generated from selective breeding, come to be ideal models for understanding the molecular mechanisms underlying different phenotypes. The Chicken Genome Project provides a large amount of information for research using chicken as the model. This review summarizes the development of the Chicken Genome Project, as well as the strategies for researching the quantitative traits of different chicken strains using the information of the Chicken Genome. We also give a perspective of the developmental and genetic studies that can be conducted using the chicken as a model organism as well as using its genomic information.

[Isolation, culture, identification and biological characteristics of chicken skeletal muscle satellite cells].

Chicken skeletal muscle satellite cells were obtained by a two-step method of collagenase-I and trypsin digestion, followed by in vitro culture. They were further identified by specific gene expression assays. In addition, cell biological characteristics and myogenic genes expression were analyzed. Results showed that satellite cells from chicken skeletal muscle tissue expressed pax7, desmin, and possessed ability to proliferate and differentiate. The technical platform was established to study the mechanism of myogenic proliferation, differentiation and muscle regeneration.

A simple method to detect the heterogeneity of nucleotide substitution processes by measuring asymmetry in paired comparison.

A simple method is presented, which uses a chi2 statistic to measure asymmetry of the substitution matrix between two DNA sequences in order to test a homogeneity hypothesis of the substitution processes. In theory, this chi2 test holds irrespective of whether there is among-site (i) heterogeneity in substitution rates, (ii) correlation in evolutionary rates/models, and (iii) variation in substitution models. Computer simulations showed that the chi2 test is powerful under a variety of models of sequence evolution. Comparison of the eleven sequenced arthropod mtDNAs by using this test revealed that most of the observed evolutionary models were homogeneous between the two mosquitoes but not between Daphnia pulex or Artemia franciscan and the other arthropods, probably due to shifts to a high AT content. A comparison to Kumar and Gadagkar's test by computer simulation as well as empirical data analysis is also given.

[Altered expression of myostatin gene in the progressive muscular dystrophy patients].

Progressive muscular dystrophy is a group of inherited disorders characterized by progressive skeletal muscle wasting and weakness, which is not of neurogenic origin. Myostatin, a new member of the TGF-beta super-family, is a negative regulator of skeletal muscle growth. To investigate the possible involvement of myostatin in the development of progressive muscular dystrophy, we cloned and sequenced myostatin cDNAs from the progressive muscular dystrophy patients by RT-PCR. Levels of myostatin mRNA and protein in the patients were analyzed by semi-quantitative RT-PCR and Western blot,respectively. We did not find any mutations in the myostatin cDNA sequences from the progressive muscular dystrophy patients in this study. However, we found that the levels of myostatin transcripts were reduced in some patients and the processing and maturation of myostatin protein were inhibited in some patients. Our data demonstrated that the pathogenesis of some types or subtypes of progressive muscular dystrophy is probably associated with the altered myostatin expression and the processing inhibition of myostatin protein.

[Genes and their functional mechanisms in the pathogenesis of muscular dystrophy].

Muscular dystrophy (MD), a group of inherited disorders characterized by progressive skeletal muscle wasting and weakness, can be classified into several groups according to Mendelian inheritance patterns and clinical features. Many genes related to MD have been identified and cloned by genetic linkage analysis and positional cloning strategy. Our understanding of the molecular mechanisms giving rise to muscular dystrophy have made a progress by the functional analysis of proteins encoded by candidate genes for MD. This article reviews genes and their functional mechanisms in the pathogenesis of muscular dystrophy.

[Functional characterization of recombinant myostatin and its inhibitory role to chicken muscle development].

Myostatin is a recently discovered member of transforming growth factor beta (TGFbeta) superfamily and shares similar structure features with other members of TGFbeta superfamily. For a better understanding of molecular mechanism of myostatin function, the production of C-terminal truncated form of recombinant myostatin protein (rMSTN) in E. coli was previously reported. Herein, the functional role of the recombinant myostatin in regulating myogenesis in a chicken embryonic myoblasts (CEMs) system was determined. By using flow cytometric analysis, the myostatin was found to inhibit cell cycle transition from G1 to S phase and result in a cell cycle arrest at G1. In addition, myostatin blocked the multi-nucleus myotube formation and caused a decreased expression of the muscle cell differentiation markers (myogenin and MHC) in CEMs. In this study, a rabbit polyclonal antibody against myostatin was produced and high affinity and specificity of this anti-myostatin antibody to recombinant and endogenous myostatin were assayed by Western blot analysis. Further studies showed that the antibody could also recognize the tissue endogenous myostatin of human, mouse and rat. A specific 40 kD band was detected in chicken muscle, which suggested that chicken myostatin might have different splicing pattern. Immunofluorescence assay indicated that myostatin predominantly existed in the cytosol in C2C12 cells. Taken together, the results show that myostatin inhibits chicken muscle cells proliferation and differentiation and down-regulates expression of two differentiation marker gene in CEMs. Remarkably, production of functional recombinant myostatin protein and its specific antibody provides important reagents for unraveling molecular mechanisms underlying myostatin action during myogenesis.

[Functional roles of the plant superoxide dismutase].

Superoxide Dismutases (SODs) are ubiquitously expressed antioxidant enzyme in aerobic organisms and catalyze dismutation of superoxide anion to hydrogen and molecular oxygen, the first step in active oxygen-scavenging systems. SODs play a central role in protecting cells against the toxic effects of reactive oxygen species generated during normal cellular metabolic activity or as a result of various environmental stresses. This paper reviews the expression and regulation of Sod genes and their functional role(s) during development and in response to stresses.

[Functions of Smad and its binding proteins in TGF beta signal pathway].

Members of transforming growth factor-beta(TGF beta) superfamily play an important roles in regulating cell growth, differentiation and tissue homeostasis. The multi-functional roles of TGF beta are performed by phosphorylating their downstream factor Smad. It has been recently reported that Smad can physically associate with different cytosolic protein factors,such as transcription factors, coactivators and corepressors. In the TGF beta signal transduction pathways, the activated Smad directively interact with those factors to form different Smad/factors complexes which are then translocated from cytoplasm to nucleus where they regulate different TGF beta responsive gene expression for its mutifunctional roles in cells.

[Single nucleotide polymorphism analysis of the chicken Myostatin gene in different chicken lines].

Myostatin is a new member of the TGF-beta superfamily. It is specifically expressed in skeletal muscle cells and functions as a negative regulator of skeletal muscle growth. This study was aimed to identify the single nucleotide polymorphisms (SNPs) of Myostatin gene in various breeds including Beijing Youji, Baierji, Shiqiza, Dwarf Yellow Chickens, Mini Yellow Chickens, Huiyang Huxuji, Recessive White Chickens, AA and Hyline Layer. The 17 pairs of primers for Myostatin gene were designed based on the chicken genomic sequence. The total 5 SNPs were identified in the chicken Myostatin gene by PCR-SSCP of which 3 were in the 5'-regulatory region and 2 were in the 3'-regulatory region of the Myostatin gene in different chicken lines. The sequence data showed that one of the three SNPs localized in the 5'-regulatory region was due to 3 single point mutations (G304A, A322G, C334T, respectively), other two were single point mutation of G167A and T177C, respectively. The other two SNPs in the 3'-regulatory region of the Myostatin gene are A to T (7263) and A to G (6935). Population genetic analysis indicated that genotype frequencies of the Myostatin locus (P60/P61) in Beijing youji were quite different from those of other tested chicken lines. Frequency of the BB genotype was very high (0.70) while the AA genotype was only 0.033 in 5'-regulatory region (P60/P61) in Beijing youji population. The genotype frequencies (P93/P94) were significantly different among the lines (P < 0.01): frequencies of the EE genotype in Beijing Youji were lower than those in the other lines, while frequencies of the EE genotype in Baierji and Hyline Layer were higher than the rest. Frequency of allele C (P80/P81) in 9 breeds was higher than that of allele D. Frequency of genotype MM (P76/P77) was low, and that of MN was high in 7 breeds.

[Single nucleotide polymorphism analysis in chicken leptin receptor exon 9].

Leptin receptor is a type I cytokine super family member and plays an important role in leptin functioning signal transduction. This study was designed to investigate the single nucleotide polymorphism (SNP) of OBR gene in various breeds, including Fatness Line (FL), Leanness Line (LL), Beijing Youji, Baierji, Shiqiza, Dwarf Yellow Chickens, Mini Yellow Chickens, Huiyang Huxuji, Recessive White Chickens and Hyline Layer. The primers for exon 9 in OBR gene were designed from the database of chicken genomic sequence and the SNPs were detected by PCR-SSCP method. One SNP (C/A at 1167 in cds) was found among individuals within all breeds. However, the amino acid was not changed because it was a silence mutation. The result of population genetics analyses showed that the frequency of AA genotype in Beijing Youji was significantly higher than that in other lines. Also, the frequency of A allele in FL was significantly higher than that in LL.

[MEF2 and myogenesis].

Recent genetic and biochemical studies have demonstrated that skeletal muscle growth and differentiation in vertebrates are controlled by a core regulatory network which consists of two families of transcriptional factors, the MyoD group basic helix-loop-helix (bHLH) muscle regulatory factors (MRFs) and the myocyte enhancer factor 2 (MEF2) group of MADS-box regulators. During development, MEF2 interacts genetically and physically with different members of this myogenic network and together they cooperate to positively or negatively regulate transcription of downstream muscle-specific differentiation genes. This paper reviews current understanding of molecular mechanism of these interactions and essential roles that MEF2 plays in skeletal muscle growth and differentiation during development.