Comparative analysis of microsatellites in coding regions provides insights into the adaptability of the giant panda, polar bear and brown bear.

Short Tandem repeats (STRs) often occur within coding regions and adaptive selection could play a vital role in shaping the landscape of coding STRs. Here, we identified 849, 1282 and 1501 genes that contained 966, 1565 and 1921 STRs in the coding regions of the giant panda, polar bear and brown bear genomes, respectively. The results showed that coding STRs were subject to strong selection on STR type, motif, repetition and mode of evolution. Coding STRs were primarily found in regulatory genes. Of the three ursids studied, we found 585 differential genes in the giant panda. Gene Ontology analysis showed that the significant enrichment term (insulin-like growth factor receptor signaling pathway) exerted direct carbohydrate metabolic effects in vivo in this species. The enrichment of this pathway suggested that the giant panda's ability to absorb carbohydrates (starch) and adapt to a bamboo diet might be enhanced by variable coding STRs. We also identified 377 conserved coding STRs located in 377 genes across the three species. Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that these genes were significantly enriched in two pathway involved in key physiological processes, including cardiovascular function and energy metabolism regulation. This study provides an important resource for future studies on the regulation of rapid diet and environmental adaptation of species by coding STRs.

Development and Application of Potentially Universal Microsatellite Markers for Pheasant Species.

Pheasants are widely distributed in the southwest of China, but many of them are endangered due to habitat fragmentation and environmental changes. Genetic diversity is crucial for species to maintain their evolutionary potential, and thus it is important to develop universal genetic markers for facilitating the assessment of genetic diversity and planning effective conservation actions in these endangered species. In this study, 471 microsatellite loci which are common among eight pheasant species were screened based on genome data, and 119 loci were selected to develop microsatellite markers. After PCR amplifications and reaction condition optimizations, and validation of microsatellite loci in 14 species of 11 genera within Phasianidae. Finally, 49 potentially universal microsatellite markers in pheasant species were obtained. These microsatellite markers were successfully applied to assess the genetic diversity of 3 pheasant species. The Sichuan hill partridge (Arborophila rufipectus), blood pheasant (Ithaginis cruentus), buff-throated partridge (Tetraophasis szechenyii) and Sichuan hill partridge had a relatively low genetic diversity level. These 49 microsatellite loci are potentially universal microsatellite loci for pheasants and are of great significance to establish a shared platform in population genetics study of pheasants.

Subcellular localization of caspase-3 activation correlates with changes in apoptotic morphology in MOLT-4 leukemia cells exposed to X-ray irradiation.

Caspase-3 is a critical effector caspase for apoptosis, which cleaves proteins, including cytoskeletal and associated proteins, kinases, and members of the Bcl-2 family of apoptosis-related proteins. This leads to changes in apoptotic morphology, such as membrane externalization and cytoplasm and nuclear condensation. It has been reported that pro-caspase-3 is activated in the cytosol. However, it remains obscure how caspase-3 activation correlates to serial changes in cell morphology during apoptosis. The current study was therefore undertaken to assess the relationship between caspase-3 activation and its subcellular localization and alterations in apoptotic morphology in MOLT-4 human leukemia cells exposed to X-ray irradiation. Fluorescence labeled inhibitor of caspases (FLICA) was used to detect caspase-3 activity in apoptotic cells in this project; cell morphology and caspase-3 sub-localization were determined by confocal microscopy. Our data showed that MOLT-4 cells presented typical morphological changes in apoptosis, such as membrane reversion, DNA fragmentation, and formation of apoptotic cell bodies following 10 Gray (Gy) of X-ray irradiation. Caspase-3 was activated 2 h after X-ray irradiation, and its activity increased markedly after 4-6-h exposure. Membrane reversion in MOLT-4 leukemia cells was detected by Annexin V assay at 4 h following X-ray irradiation, 2 h after the elevated caspase-3 activity was measured. Cytologically, activation of caspase-3 was first observed close to the inside surface of the cellular membrane, then transferred to the cytoplasm, and finally translocated to the nuclear region. We conclude that caspase-3 is activated in MOLT-4 cells following exposure to X-rays, and that the enhanced caspase-3 activity and its sub-localization shifting is correlated to changes in apoptotic morphology. The spatial shift of activated caspase-3 in X-ray-induced apoptotic MOLT-4 leukemia cells is a process of crucial importance for apoptosis.

Nuclear accumulation of epidermal growth factor receptor and acceleration of G1/S stage by Epstein-Barr-encoded oncoprotein latent membrane protein 1.

Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) is considered to be the major oncogenic protein of EBV-encoded proteins and has always been the core of the oncogenic mechanism of EBV. Advanced studies on nuclear translocation of the epidermal growth factor receptor (EGFR) family have greatly improved our knowledge of the biological function of cell surface receptors. In this study, we used the Tet-on LMP1 HNE2 cell line as a cell model, which is a dual-stable LMP1-integrated nasopharyngeal carcinoma (NPC) cell line and the expression of LMP1 which could be regulated by the Tet system. We found that LMP1 could regulate the nuclear accumulation of EGFR in a dose-dependent manner quantitatively and qualitatively. We also demonstrated that the nuclear localization sequence of EGFR played some roles in the location of the protein within the nucleus under LMP1 regulation and EGFR in the nucleus could bind to the promoters of cyclinD1 and cyclinE, respectively. We further demonstrated that EGFR is involved in the acceleration of the G1/S phase transition by LMP1 through binding to cyclinD1 and cyclinE directly. These findings provided a novel view that the acceleration of LMP1 on the G1/S transition via the nuclear accumulation of EGFR was critical in the process of nasopharyngeal carcinoma.