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LR1 is a B cell-specific, sequence-specific DNA binding activity that regulates transcription in activated B cells. LR1 also binds Ig heavy chain switch region sequences and may function in class switch recombination. LR1 contains two polypeptides, of 106 kDa and 45 kDa, and here we report that the 106-kDa component of LR1 is nucleolin. This identification, initially made by microsequence analysis, was verified by showing that (i) LR1-DNA binding activity increased in B cells transfected with a nucleolin cDNA expression construct; (ii) LR1-DNA binding activity was recognized by antibodies raised against recombinant human nucleolin; and (iii) in B cells transfected with epitope-tagged nucleolin expression constructs, the LR1-DNA complex was recognized by the anti-tag antibody. Nucleolin is an abundant nucleolar protein which is believed to play a role in rDNA transcription or organization, or rRNA processing. Homology between nucleolin and histone H1 suggests that nucleolin may alter DNA organization in response to cell cycle controls, and the nucleolin component of LR1 may therefore function to organize switch regions before, during, or after switch recombination. The demonstration that nucleolin is a component of a B cell-specific complex that binds switch region sequences suggests that the G-rich switch regions may have evolved from rDNA.

Abstract Background RNA based antiviral approaches against HIV-1 are among the most promising for long-term gene therapy. These include ribozymes, aptamers (decoys), and small interfering RNAs (siRNAs). Lentiviral vectors are ideal for transduction of such inhibitory RNAs into hematopoietic stem cells due to their ability to transduce non-dividing cells and their relative refractiveness to gene silencing. The objective of this study is to introduce an HIV-1 Tar aptamer either alone or in combination with an anti-CCR5 ribozyme into CD34+ hematopoietic progenitor cells via an HIV-based lentiviral vector to derive viral resistant progeny T cells and macrophages. Results High efficiency and sustained gene transfer into CD34+ cells were achieved with lentiviral vector constructs harboring either Tar decoy or Tar decoy in combination with CCR5 ribozyme. Cells transduced with these constructs differentiated normally into T-lymphocytes in vivo in thy/liv grafts of SCID-hu mice, and into macrophages in vitro in the presence of appropriate growth factors. When challenged in vitro, the differentiated T lymphocytes and macrophages showed marked resistance against HIV-1 infection. Conclusions Viral resistant transgenic T cells and macrophages that express HIV-1 Tar aptamer either alone or in combination with an anti-CCR5 ribozyme could be obtained by lentiviral gene transduction of CD34+ progenitor cells. These results showed for the first time that expression of these anti-HIV-1 transgenes in combination do not interfere with normal thymopoiesis and thus have set the stage for their application in stem cell based gene therapy for HIV/AIDS.

Mirabilis himalaica (Edgew.) Heimerl is among the most important genuine medicinal plants in Tibet. However, the biosynthesis mechanisms of the active compounds in this species are unclear, severely limiting its application. To clarify the molecular biosynthesis mechanism of the key representative active compounds, specifically rotenoid, which is of special medicinal value for M. himalaica, RNA sequencing and TOF-MS technologies were used to construct transcriptomic and metabolomic libraries from the roots, stems, and leaves of M. himalaica plants collected from their natural habitat. As a result, each of the transcriptomic libraries from the different tissues was sequenced, generating more than 10 Gb of clean data ultimately assembled into 147,142 unigenes. In the three tissues, metabolomic analysis identified 522 candidate compounds, of which 170 metabolites involved in 114 metabolic pathways were mapped to the KEGG. Of these genes, 61 encoding enzymes were identified to function at key steps of the pathways related to rotenoid biosynthesis, where 14 intermediate metabolites were also located. An integrated analysis of metabolic and transcriptomic data revealed that most of the intermediate metabolites and enzymes related to rotenoid biosynthesis were synthesized in the roots, stems and leaves of M. himalaica, which suggested that the use of non-medicinal tissues to extract compounds was feasible. In addition, the CHS and CHI genes were found to play important roles in rotenoid biosynthesis, especially, since CHS might be an important rate-limiting enzyme. This study provides a hypothetical basis for the screening of new active metabolites and the metabolic engineering of rotenoid in M. himalaica. [ABSTRACT FROM AUTHOR]

Key message: The transcriptome profiling in replanting roots revealed that expression pattern changes of key genes promoted important metabolism pathways, antioxidant and pathogen defense systems, adjusted phytohormone signaling and inhibited lignin biosynthesis.Abstract: The yield of the medicinal plant Achyranthes bidentata could be significantly increased when replanted into a field cultivated previously for the same crop, but the biological basis of this so-called “replanting benefit” is unknown. Here, the RNA-seq technique was used to identify candidate genes responsible for the benefit. The analysis of RNA-seq libraries prepared from mRNA extracted from the roots of first year planting (normal growth, NG) and second year replanting (consecutive monoculture, CM) yielded about 40.22 GB sequencing data. After de novo assembly, 87,256 unigenes were generated with an average length of 1060 bp. Among these unigenes, 55,604 were annotated with public databases, and 52,346 encoding sequences and 2881 transcription factors were identified. A contrast between the NG and CM libraries resulted in a set of 3899 differentially transcribed genes (DTGs). The DTGs related to the replanting benefit and their expression profiles were further analyzed by bioinformatics and qRT-PCR approaches. The major differences between the NG and CM transcriptomes included genes encoding products involved in glycolysis/gluconeogenesis, glutathione metabolism and antioxidant defense, in aspects of the plant/pathogen interaction, phytohormone signaling and phenylpropanoid biosynthesis. The indication was that replanting material enjoyed a stronger level of defense systems, a balance regulation of hormone signals and a suppression of lignin formation, thereby promoting root growth and development. The study provides considerable significant insights for a better understanding of the molecular mechanism of the replanting benefit and suggests their possible application in developing methods to reinforce the effects in medicinal plants. [ABSTRACT FROM AUTHOR]

Rehmannia glutinosa Libosch. is a medicinal plant cultivated at a commercial scale in China. However, replanting problems result in a severe decline in both the biomass and quality of its roots, which are of greatest medicinal value. This study attempted to remediate the replant soil using spent Pleurotus eryngii Quel substrate for alleviating this issue, and to investigate the underlying mechanisms. Results showed that R. glutinosa grew successfully in fresh soil and remedial replant soil, while no roots were harvested in the unremedied replant soil. Overall, the nutritional status in the remedial soil was higher than that of the unremedied and fresh soil, while the concentration of allelopathic phenolic acids was lower. When planted in unremedied soil, the growth of five plant pathogens was induced and one beneficial fungus was suppressed. When planted in remedied soil, four out of the five pathogens were suppressed, while two beneficial fungi were identified in the remedial soil. This study suggests that the spent P. eryngii substrate significantly alleviates the replant problem of R. glutinosa, and that the alleviatory function reflects a synergetic effect, including the supplementation of soil nutrition, the degradation of allelochemicals, and the remediation of unbalanced microbial community. [ABSTRACT FROM AUTHOR]