The cotton mitochondrial chimeric gene orf610a causes male sterility by disturbing the dynamic balance of ATP synthesis and ROS burst

Plant cytoplasmic male sterility(CMS)is maternally inherited and often manifested as aborted pollen development,but the molecular basis of abortion remains to be identified.To facilitate an investigation of CMS in cotton,the complete sequence of cotton mitochondrial(mt)genome for CMS-D2 line ZBA was determined.The mt genome was assembled as a single circular molecule with 634,036 bp in length.A total of 194 ORFs,36 protein-coding genes,six r RNAs,and 24 t RNAs were identified.Several chimeric genes encoding hypothetical proteins with transmembrane domains were identified.Among them,a previously unknown chimeric gene,orf610a,which is composed of atp1 and a 485-bp downstream sequence of unknown nature,was identified.RT-PCR and q RT-PCR validation indicated that orf610a was expressed specifically in a sterile line.Ectopic expression of orf610a in yeast resulted in excessive accumulation of reactive oxygen species and reduction in ATP content,in addition to inhibition of cellular growth.Transgenic A.thaliana overexpressing orf610a fused with a mitochondrial targeting peptide displayed partial male sterility.Interaction between ORF610a and the nuclear-encoded protein RD22 indicated an association between ORF610a and pollen abortion.Positive feedback during transcriptional regulation between nuclear regulatory factors and the mt CMS gene may account for the male sterility of ZBA.

Cotton Plants Transformed with the Activated Chimeric Cry1Ac and API-B Genes

A chimeric gene, Bt29K, composed of coding sequences of activated Cry1Ac insecticidal protein and an endoplasm reticulum-retarding signal peptide, was synthesized. A plant expression vector containing two expression cassettes for the Bt29K and API-B genes was constructed. These two insect-resistant genes were transferred into two cotton ( Gossypium hirsutum L.) varieties ( or lines) via Agrobacterium-mediated transformation and nine homozygous transgenic cotton lines showing a mortality of 90.0% - 99.7% to cotton ballworm (Heliothis armigera) larvae and good agronomic traits were selected through six generations. Molecular biology analysis revealed that one or two copies of the insecticidal protein genes were integrated into the transgenic cotton genome and activated Cry1Ac and API-B protein expression was at a level of 0.17% and 0.09% of the total soluble protein in the transgenic cotton leaves, respectively. Comparison of the insect-resistance of the homozygous lines expressing the activated chimeric Cry1Ac and API-B with that expressing Cry1Ac only revealed that the insect-resistance of the former is apparently higher than the latter. These results also indicate that the strategy to construct a plant expression vector expressing two different insect-resistant genes reported here is reasonable.

The chimeric genes in the hybrid lineage of Carassius auratus cuvieri(♀)×Carassius auratus red var.(♂)

Hybridization can combine the genomes of different strains or species, which leads to changes of genotype and phenotype in the hybrids. In this study, we aimed to investigate the genetic variations of hybrids(WR-F1 and WR-F2) derived from the intraspecific hybridization of white crucian carp(Carassius auratus cuvieri, WCC, ♀) and red crucian carp(Carassius auratus red var., RCC, ♂). Here, we compared the orthologous genes in the liver transcriptomes of hybrids with those of WCC and RCC, and classified the orthologous genes into eight gene patterns within three categories(chimera, mutant, and biparental origin genes).The results revealed 19.04%, 4.17% chimeric genes and 6.90%, 5.05% mutations of orthologous genes in WR-F1 and WR-F2 respectively. Seventeen of twenty-three characterized genes(77%) were confirmed to be the chimeras at the genomic DNA level.The GO classification discovered that some chimeric and mutant genes were related to metabolic process, immune system and developmental process in WR-F1. Our results provide the new evidence that hybridization can combine the parental genomes,leading to changes in the genotype of the resultant hybrids. This is the first report on the formation of chimeric genes from fish intraspecific hybridization, which is potentially interesting from the context of both evolution and the genetic breeding of fish.

In vivo anti-tumor activity of murine hematopoietic stem cells expressing a p185HER2-specific chimeric T-cell receptor gene

We have confirmed efficient anti-tumor activities of the peripheral lymphocytes transduced with a p185HEH2-specific chimeric T-cell receptor gene both in murine and in human in our previous studies. To further test the feasibility of chimeric T-cell receptor in a bone marrow transplantation model, we first, made two routine tumor cell lines： MT901 and MCA-205, to express human p185HER2 by retroviral gene transduction. Murine bone marrow cells were retrovirally transduced to express the chimeric T-cell receptor and gene-modified bone marrow cells were transplanted into lethally irradiated mouse. Six months post transplantation, p185HER2-positive tumor ceils： MT-901/HER2 or MCA-205/ HER2 was subcutaneously or intravenously injected to make mouse models simulating primary breast cancer or pulmonary metastasis. The in vivo anti-tumor effects were monitored by the size of the subcutaneous tumor or counting the tumor nodules in the lungs after India ink staining. The size of the subcutaneous tumor was significantly inhibited and the number of pulmonary nodules were significantly decreased in mouse recipients transplanted with chimeric T-cell receptor modified bone marrow cells compared with the control group. Our results suggest the efficient in vivo anti-tumor activities of chimeric T-cell receptor gene modified bone marrow cells.

On the origin and evolution of new genes——a genomic and experimental perspective

The inherent interest on the origin of genetic novelties can be traced back to Darwin. But it was not until recently that we were allowed to investigate the fundamental process of origin of new genes by the studies on newly evolved young genes. Two indispensible steps are involved in this process： origin of new gene copies through various mutational mechanisms and evolution of novel functions, which fur- ther more leads to fixation of the new copies within populations. The theoretical framework for the former step formed in 1970s. Ohno proposed gene duplication as the most important mechanism producing new gene copies. He also believed that the most common fate for new gene copies is to become pseudogenes. This classical view was validated and was also challenged by the characterization of the first functional young gene jingwei in Drosophila. Recent genome-wide comparison on young genes of Drosophila has elucidated a compre- hensive picture addressing remarkable roles of various mechanisms besides gene duplication during origin of new genes. Case surveys revealed it is not rare that new genes would evolve novel structures and functions to contribute to the adaptive evolution of organisms. Here, we review recent advances in understanding how new genes originated and evolved on the basis of genome-wide results and ex- perimental efforts on cases. We would finally discuss the future directions of this fast-growing research field in the context of functional genomics era.

Tumor Antigen Specific Activation of Primary Human T-Cells Expressing a Virally Encoded Chimeric T-Cell Receptor Specific for p185HER2

We have developed and tested chimeric T-cell receptors (TCR) specific for p185HER2. In these experiments, retroviral vectors expressing the N29γ or N29ζ receptors were constructed in pRET6. Amphotropic viral producer cells were established in the GALV-based PG13 packaging cell line. Ficoll purified human peripheral blood lymphocytes (PBL) were virally transduced using an optimized protocol incorporating activation with immobilized anti-CD3/anti-CD28 monoclonal anti- bodies, followed by viral infection in the presence of fibronectin fragment CH296. Transduced cells were co-cultured with human tumor cell lines that overexpress (SK-OV-3) or underexpress (MCF7) p185HER2 to assay for antigen specific im- mune responses. Both CM+ and CD8+ T-cells transduced with the N29γ or N29ζ chTCR demonstrated HER2-specific anti- gen responses, as determined by release of Th1 like cytokines, and cellular cytotoxicity assays. Our results support the fea- sibility of adoptive immunotherapy with genetically modified T-cells expressing a chTCR specific for p185HER2.

The new chimeric chiron genes evolved essential roles in zebrafish embryonic development by regulating NAD+ levels

The origination of new genes is important for generating genetic novelties for adaptive evolution and biological diversity.However, their potential roles in embryonic development, evolutionary processes into ancient networks, and contributions to adaptive evolution remain poorly investigated. Here, we identified a novel chimeric gene family, the chiron family, and explored its genetic basis and functional evolution underlying the adaptive evolution of Danioninae fishes. The ancestral chiron gene originated through retroposition of nampt in Danioninae 48–54 million years ago(Mya) and expanded into five duplicates(chiron1–5) in zebrafish 1–4 Mya. The chiron genes(chirons) likely originated in embryonic development and gradually extended their expression in the testis. Functional experiments showed that chirons were essential for zebrafish embryo development. By integrating into the NAD^(+) synthesis pathway, chirons could directly catalyze the NAD^(+) rate-limiting reaction and probably impact two energy metabolism genes(nmnat 1 and naprt) to be under positive selection in Danioninae fishes. Together,these results mainly demonstrated that the origin of new chimeric chiron genes may be involved in adaptive evolution by integrating and impacting the NAD^(+) biosynthetic pathway. This coevolution may contribute to the physiological adaptation of Danioninae fishes to widespread and varied biomes in Southeast Asian.

Spotlight on chimeric antigen receptor engineered T cell research and clinical trials in China

T cell mediated adoptive immune response has been characterized as the key to anti-tumor immunity. Scientists around the world including in China, have been trying to harness the power of T cells against tumors for decades. Recently, the biosynthetic chimeric antigen receptor engineered T cell(CAR-T) strategy was developed and exhibited encouraging clinical efficacy, especially in hematological malignancies. Chimeric antigen receptor research reports began in 2009 in China according to our Pub Med search results. Clinical trials have been ongoing in China since 2013 according to the trial registrations on clinicaltrials.gov.. After years of assiduous efforts, research and clinical scientists in China have made their own achievements in the CAR-T therapy field. In this review, we aim to highlight CAR-T research and clinical trials in China, to provide an informative reference for colleagues in the field.