Germline Stem Cell Gene PIWIL2 Mediates DNA Repair through Relaxation of Chromatin

DNA damage response (DDR) is an intrinsic barrier of cell to tumorigenesis initiated by genotoxic agents. However, the mechanisms underlying the DDR are not completely understood despite of extensive investigation. Recently, we have reported that ectopic expression of germline stem cell gene PIWIL2 is associated with tumor stem cell development, although the underlying mechanisms are largely unknown. Here we show that PIWIL2 is required for the repair of DNA-damage induced by various types of genotoxic agents. Upon ultraviolet (UV) irradiation, silenced PIWIL2 gene in normal human fibroblasts was transiently activated after treatment with UV light. This activation was associated with DNA repair, because Piwil2-deficienct mouse embryonic fibroblasts (mili-/- MEFs) were defective in cyclobutane pyrimidine dimers (CPD) repair after UV treatment. As a result, the UV-treated mili-/- MEFs were more susceptible to apoptosis, as characterized by increased levels of DNA damage-associated apoptotic proteins, such as active caspase-3, cleaved Poly (ADP-ribose) polymerase (PARP) and Bik. The impaired DNA repair in the mili-/- MEFs was associated with the reductions of histone H3 acetylation and chromatin relaxation, although the DDR pathway downstream chromatin relaxation appeared not to be directly affected by Piwil2. Moreover, guanine–guanine (Pt-[GG]) and double strand break (DSB) repair were also defective in the mili-/- MEFs treated by genotoxic chemicals Cisplatin and ionizing radiation (IR), respectively. The results indicate that Piwil2 can mediate DNA repair through an axis of Piwil2 → histone acetylation → chromatin relaxation upstream DDR pathways. The findings reveal a new role for Piwil2 in DNA repair and suggest that Piwil2 may act as a gatekeeper against DNA damage-mediated tumorigenesis

A Comprehensive Expression Profile of MicroRNAs in Porcine Pituitary

MicroRNAs (miRNAs) are an abundant class of small RNAs that regulate expressions of most genes. miRNAs play important roles in the pituitary, the “master” endocrine organ.However, we still don't know which role miRNAs play in the development of pituitary tissue or how much they contribute to the pituitary function. By applying a combination of microarray analysis and Solexa sequencing, we detected a total of 450 miRNAs in the porcine pituitary. Verification with RT-PCR showed a high degree of confidence for the obtained data. According to the current miRBase release17.0, the detected miRNAs included 169 known porcine miRNAs, 163 conserved miRNAs not yet identified in the pig, and 12 potentially new miRNAs not yet identified in any species, three of which were revealed using Northern blot. The pituitary might contain about 80.17% miRNA types belonging to the animal. Analysis of 10 highly expressed miRNAs with the Kyoto Encyclopedia of Genes and Genomes (KEGG) indicated that the enriched miRNAs were involved not only in the development of the organ but also in a variety of inter-cell and inner cell processes or pathways that are involved in the function of the organ

Characterization of the complete plastid genome of of Veronica eriogyne H. Winkl., a Tibetan medicinal herb

Veronica eriogyne H. Winkl.(Plantaginaceae) is a perennial herb with high medicinal value. To better understand the molecular genetics and evolutionary of V. eriogyne, its complete plastid genome was sequenced and annotated. The assembled chloroplast genome is a circular 151,083 bp sequence, consisting of a 82,302 bp large single copy region (LSC) and a 17,449 bp small single copy region (SSC), which were flanked by a pair of 25,666 bp inverted repeats (IRs). The GC content of the chloroplast genome is 38.03%. Moreover, a total of 134 functional genes were annotated, including 88 protein-coding, 38 tRNA, and 8 rRNA genes. Phylogenetic analysis showed that V. eriogyne has close relationship with V. persica Poi. The current study provides important information for further genetic studies on Plantaginacea

Characterization of the complete chloroplast genome of Asparagus filicinus (Asparagaceae: Asparagoideae: Asparagus), a traditional Tibetan medicinal plant

Asparagus filicinus is a traditional medicinal plant with the treatment of pneumonia and cancer, which has been classified as threatened due to habitat destruction and over-harvesting. In this study, its complete chloroplast genome was assembled from the whole genome Illumina sequencing data. The circular genome was 156,674 bp long, containing a large single copy (LSC) region of 85,003 bp and a small single copy (SSC) region of 18,663 bp, which were separated by a pair of 26,504 bp inverted repeat (IR) regions. It encoded a total of 126 genes, including 72 protein-coding genes, 46 tRNA genes and eight rRNA genes. The most of gene species occurred as a single copy, while 17 gene species occurred in double copies. The overall A + T content was 62.4%, while the corresponding values of the LSC, SSC and IR regions were 64.5, 68.4 and 57.1%, respectively. Phylogenetic analysis indicated that A. filicinus was relatively close to two species belonging to the subgenus Asparagus

Chloroplast genome of Corydalis impatiens (Pall.) Fisch. ex DC. (Papaveraceae), a Tibetan medical herb

Corydalis impatiens (Pall.) Fisch. 1821. (Papaveraceae) is a Tibetan medical herb used to reduce pain, treat skin injuries, cure hepatitis, and benefit the circulatory system. In the current study, the chloroplast genome of C. impatiens was sequenced. This complete genome is a circular 197,317 bp sequence consisting of a small single-copy (SSC, 3105 bp) region, a large single-copy (LSC, 89,790 bp) region, and a pair of inverted repeats (IRs, 52,211 bp). This chloroplast genome encodes a total of 127 functional genes, including 81 protein-coding, 38 transfer RNA, and eight ribosomal RNA genes. Furthermore, this chloroplast genome contains six pseudogenes, including a pair of ndhB a pair of ndhD, one ndhC, and one ndhK. The phylogenetic relationship within the genus Corydalis was inferred with the maximum-likelihood method, and the result showed that C. impatiens was most closely related to C. conspersa

Variation in biomass and nutrients allocation of Corydalis hendersonii on the Tibetan Plateau with increasing rainfall continentality and altitude

International audienceThe Tibetan Plateau is considered as one of most sensitive region to global change. Nutrient (N and P) availability is an important limiting ecological factor in cold terrestrial ecosystems such as the alpine belt of the Tibetan Plateau. We focused on Corydallis hendersonii, an endemic alpine species of the Tibetan Plateau. Exploring the N and P below- and above-ground responses of C. hendersonii to climatic factors is crucial for biodiversity conservation of the alpine Tibetan plateau under global change. We used the Outlying Mean Index and regression analyses to assess N and P stoichiometry and biomass responses in leaves and roots of C. hendersonii along climatic gradients. We found that investment and allocation of nutrient and biomass in C. hendersonii were mainly driven by rainfall continentality. In the eastern less-continental wet area of the Tibetan plateau, C. hendersonii had higher biomass in leaf, and lower N and P investment in roots than in the western more continental dry part. Specifically, 300 mm year−1 Mean annual precipitation (MAP) and ca. 80° Rainfall continentality index (GAMS) were threshold values of climate stress inducing strong nutrient limitation for C. hendersonii across the Tibetan Plateau. Our results suggest that rainfall continentality is the primary climatic driver of variation in biomass and nutrients allocation of C. hendersonii on the Tibetan Plateau. Thus, global warming and drying should induce a decrease in total biomass, a reduction in leaf N and P concentrations and an increase in root/shoot ratio in the alpine region of the Tibetan Plateau

Characterization of the complete chloroplast genome of Impatiens alpicola (Balsaminaceae: Impatiens), a rare and endemic Chinese flowering plant

Impatiens alpicola is a newly recorded rare and endemic flowering plant in China, which has been regarded as threatened due to its narrow distribution and human activity. In this study, its complete chloroplast genome was assembled from the whole genome Illumina sequencing data. The circular genome was 151,366 bp long, containing a large single copy (LSC) region of 82,245 bp and a small single copy (SSC) region of 17,705 bp, which were separated by a pair of 25,708 bp inverted repeat (IR) regions. It encoded a total of 128 genes, including 76 protein-coding genes, 44 tRNA genes and eight rRNA genes. The most of gene species occurred as a single copy, while 18 gene species occurred in double copies. The overall A + T content was 63.1%, while the corresponding values of the LSC, SSC and IR regions were 65.4, 70.6, and 56.9%, respectively. Phylogenetic analysis indicated that I. alpicola was relatively close to another species (I. piufanensis) belonging to the same genus

Characterization of the complete chloroplast genome of the prickly blue poppy Meconopsis horridula Hook. f. & Thomson (Ranunculales: Papaveraceae)

The prickly blue poppy (Meconopsis horridula Hook. f. & Thomson) is a traditional Tibetan medicinal herb with high values. In this study, its chloroplast genome was determined to be 153,761 bp in length with an A + T-biased base composition, and comprises a pair of inverted repeat (IR) regions (26,030 bp), separated by a large single-copy (LSC) region (83,803 bp) and a small single-copy (SSC) region (17,898 bp). A total of 113 gene species were annotated, with 20 of them being completely or partially duplicated and 18 of them harboring one or two introns. Phylogenetic analysis suggests that M. horridula is closely related to Meconopsis racemosa Maxim

Characterization of the complete chloroplast genome of the Tangut monkshood Aconitum tanguticum (Ranunculales: Ranunculaceae)

The Tangut monkshood (Aconitum tanguticum) is a perennial herb with high medicinal values. Here, its chloroplast genome was assembled from Illumina sequencing reads. The circular genome is 157,114 bp long with an A + T-biased nucleotide composition, and comprises a pair of inverted repeat (IR) regions (26,255 bp), separated by a large single-copy (LSC) region (87,559 bp) and a small single-copy (SSC) region (17,045 bp). It encodes a total of 112 gene species, with 19 of them being completely or partially duplicated and 18 of them harboring one or two introns. Phylogenetic analysis recovered two major clades of the genus Aconitum