Enrichment of a common wheat genetic map and QTL mapping for fatty acid content in grain

DArT and SSR markers were used to saturate and improve a previous genetic map of RILs derived from the cross Chuan35050 × Shannong483. The new map comprised 719 loci, 561 of which were located on specific chromosomes, giving a total map length of 4008.4 cM; the rest 158 loci were mapped to the most likely intervals. The average chromosome length was 190.9 cM and the marker density was 7.15 cM per marker interval. Among the 719 loci, the majority of marker loci were DArTs (361); the rest included 170 SSRs, 100 EST-SSRs, and 88 other molecular and biochemical loci. QTL mapping for fatty acid content in wheat grain was conducted in this study. Forty QTLs were detected in different environments, with single QTL explaining 3.6-58.1% of the phenotypic variations. These QTLs were distributed on 16 chromosomes. Twenty-two QTLs showed positive additive effects, with Chuan35050 increasing the QTL effects, whereas 18 QTLs were negative with increasing effects from Shannong483. Six sets of co-located QTLs for different traits occurred on chromosomes 1B, 1D, 2D, 5D, and 6B.     

外源基因在转基因动物中遗传和表达的稳定性

转基因技术经过近半个世纪的发展,已成为当今生物技术研究的热点。近10多年来,与核移植技术的结合,转基因效率大大提高,携带有不同外源基因的不同种类的转基因动物迅速增加。但是,成功获得转基因动物并不是转基因动物研究的最终目的,如何利用转基因技术为人类的需求服务才是科研人员始终面对的课题。在畜牧生产领域,通过转基因技术培育家畜新品种是转基因技术应用的重要体现,在我国这方面已经引起了广泛关注。但迄今为止,外源基因在转基因动物中遗传和表达的稳定性仍然是亟待解决的问题,究其原因,这主要与位置效应、外源基因的表观遗传学修饰和遗传效率相关,文章结合目前的研究进展和本实验室的研究结果,从这3方面阐述其作用机制,期望为转基因动物遗传育种向产业化的迈进提供一定的理论探讨。     

OVCA1 inhibits the proliferation of epithelial ovarian cancer cells by decreasing cyclin D1 and increasing p16

OVCA1, a tumor suppressor gene, is deleted or lower expressed in about 80% of ovarian cancer. Over expression of OVCA1 in human ovarian cancer A2780 cells inhibits cell proliferation and arrests cells in G1 stage. However, the fact that the molecular mechanism of OVCA1 inhibits cell growth is presently elusive. Here we investigated the potential signaling pathway induced by over-expression of OVCA1. Our results show that over-expression of human OVCA1 in ovarian cancer cells A2780 leads to down-regulation of cyclin D1, and up-regulation of p16, but no effect on the expression of NF-κB. It indicates that OVCA1 could inhibit the proliferation of ovarian cancer cell A2780 by p16/cyclin D1 pathway, but not by NF-κB.     

Survival and differentiation of mammary epithelial cells in mammary gland development require nuclear retention of Id2 due to RANK signaling

RANKL plays an essential role in mammary gland development during pregnancy. However, the molecular mechanism by which RANK signaling leads to mammary gland development is largely unknown. We report here that RANKL stimulation induces phosphorylation of Id2 at serine 5, which leads to nuclear retention of Id2. In lactating Id2Tg; RANKL(-/-) mice, Id2 was not phosphorylated and was localized in the cytoplasm. In addition, in lactating Id2(S5A)Tg mice, Id2(S5A) (with serine 5 mutated to alanine) was exclusively localized in the cytoplasm of mammary epithelial cells (MECs), while endogenous Id2 was localized in the nucleus. Intriguingly, nuclear expression of Id2(S5A) rescued increased apoptosis and defective differentiation of MECs in RANKL(-/-) mice. Our results demonstrate that nuclear retention of Id2 due to RANK signaling plays a decisive role in the survival and differentiation of MECs during mammary gland development.     

The airway antigen sampling system: respiratory M cells as an alternative gateway for inhaled antigens

In this study, we demonstrated a new airway Ag sampling site by analyzing tissue sections of the murine nasal passages. We revealed the presence of respiratory M cells, which had the ability to take up OVA and recombinant Salmonella typhimurium expressing GFP, in the turbinates covered with single-layer epithelium. These M cells were also capable of taking up respiratory pathogen group A Streptococcus after nasal challenge. Inhibitor of DNA binding/differentiation 2 (Id2)-deficient mice, which are deficient in lymphoid tissues, including nasopharynx-associated lymphoid tissue, had a similar frequency of M cell clusters in their nasal epithelia to that of their littermates, Id2(+/-) mice. The titers of Ag-specific Abs were as high in Id2(-/-) mice as in Id2(+/-) mice after nasal immunization with recombinant Salmonella-ToxC or group A Streptococcus, indicating that respiratory M cells were capable of sampling inhaled bacterial Ag to initiate an Ag-specific immune response. Taken together, these findings suggest that respiratory M cells act as a nasopharynx-associated lymphoid tissue-independent alternative gateway for Ag sampling and subsequent induction of Ag-specific immune responses in the upper respiratory tract.     

Atg3-mediated lipidation of Atg8 is involved in encystation of Acanthamoeba

Autophagy is a catabolic process involved in the degradation of a cell's own components for cell growth, development, homeostasis, and the recycling of cellular products. Autophagosome is an essential component in the protozoan parasite during differentiation and encystation. The present study identified and characterized autophagy-related protein (Atg) 3, a member of Atg8 conjugation system, in Acanthamoeba castellanii (AcAtg3). AcAtg3 encoding a 304 amino acid protein showed high similarity with the catalytic cysteine site of other E2 like enzymes of ubiquitin system. Predicted 3D structure of AcAtg3 revealed a hammer-like shape, which is the characteristic structure of E2-like enzymes. The expression level of AcAtg3 did not increase during encystation. However, the formation of mature cysts was significantly reduced in Atg3-siRNA transfected cells in which the production of Atg8-phosphatidylethanolamine conjugate was inhibited. Fluorescent microscopic analysis revealed that dispersed AcAtg3-EGFP fusion protein gathered around autophagosomal membranes during encystation. These results provide important information for understanding autophagic machinery through the lipidation reaction mediated by Atg3 in Acanthamoeba.     

Prevalence of Clonorchis sinensis metacercariae in freshwater fish from three latitudinal regions of the Korean Peninsula

A large-scale survey was conducted to investigate the infection status of fresh water fishes with Clonorchis sinensis metacercariae (CsMc) in 3 wide regions, which were tentatively divided by latitudinal levels of the Korean peninsula. A total of 4,071 freshwater fishes were collected from 3 regions, i.e., northern (Gangwon-do: 1,543 fish), middle (Chungcheongbuk-do and Gyeongsangbuk-do: 1,167 fish), and southern areas (Jeollanam-do, Ulsan-si, and Gyeongsangnam-do: 1,361 fish). Each fish was examined by the artificial digestion method from 2003 to 2010. In northern areas, only 11 (0.7%) fish of 2 species, Pungtungia herzi and Squalidus japonicus coreanus from Hantan-gang, Cheolwon-gun, Gangwon-do were infected with av. 2.6 CsMc. In middle areas, 149 (12.8%) fish were infected with av. 164 CsMc. In southern areas, 538 (39.5%) fish were infected with av. 159 CsMc. In the analysis of endemicity in 3 regions with an index fish, P. herzi, 9 (6.2%) of 146 P. herzi from northern areas were infected with av. 2.8 CsMc. In middle areas, 34 (31.8%) of 107 P. herzi were infected with av. 215 CsMc, and in southern areas, 158 (92.9%) of 170 P. herzi were infected with av. 409 CsMc. From these results, it has been confirmed that the infection status of fish with CsMc is obviously different among the 3 latitudinal regions of the Korean peninsula with higher prevalence and burden in southern regions.     

Expression of the IgSF protein Kirre in the rat central nervous system

AimsImmunoglobulin superfamily (IgSF) proteins play a critical role in development of the nervous system. Here, a new member of IgSF gene family was cloned from rat brain, which was subsequently identified as rat homolog of Drosophila Kirre. This new molecule was named as rat Kirre (rKirre). We aimed to reveal the developmental expression of rKirre, both at mRNA and protein levels, in the central nervous system. The deduced amino acid sequence of rKirre showed a putative PDZ binding motif at the C-terminus, which provided a rationale for analyzing the co-localization of rKirre and post-synaptic density protein 95 (PSD-95) in cultured rat cortical neurons.Main methodscDNA library screening was used in the isolation of cDNA. Northern blotting and Western blotting were used to reveal the levels of rKirre expression. In situ hybridization and immuno-fluorescent staining were used to determine the localization of rKirre.Key findingsThe rKirre gene was found to be highly expressed in the cerebrum, hippocampus, cerebellum, brain stem and spinal cord of adult rats. In parallel, the protein level of rKirre was also increased in a developing cerebral cortex. In cultured rat cortical neurons, the amount of rKirre was significantly increased during neuronal differentiation. Immuno-cytofluorescent staining indicated that rKirre was present along the neurites of cortical neurons, and was co-localized with PSD-95.SignificanceThese results suggested that rKirre might play an essential role in neuronal differentiation and development in the central nervous system.