Regulation of gene expression via control of transcription elongation during immune responses / 中国免疫学杂志

Transcription is a multi-stage process that coordinates several steps during the transcription cycle including pre-initiation,initiation and elongation.Recent advances by genome-wide study suggest that control of transcription elongation is a critical step for precise regulation of gene expression across species from Drosophila to mammals.Here we review the molecular mechanisms of how transcription elongation of RNA polymeraseⅡ(PolⅡ) is modulated by the major pausing factors-NELF,DSIF and the positive elongation factor P-TEFb,which is the key player in pause release.We also discuss the potential implications of regulation of transcription elongation in pathogenesis of cancer,inflammation and virus infection.

Integrator complex and its research progress / 军事医学

The integrator complex is multifunctional and contains at least 12 evolutionarily conserved subunits in hu-mans.It interacts with the C-terminal tail of the largest subunit of RNA-polymeraseⅡ ( RNAPⅡ) to promote 3′-end pro-cessing of small nuclear RNA (snRNA) U1/U2.It also interacts with RNAPⅡ, NELF and Spt5 to regulate NELF-mediated RNAPⅡpause/release and processivity at coding genes .Recently, the integrator complex is also reported to be involved in DNA damage response , dynein recruitment to the nuclear envelope , integrity of Cajal bodies , adipose differentiation , hem-atopoiesis , ciliogenesis , tumorigenesis and generation of viral microRNAs .This review discusses related research progress in the integrator complex .

Alpha 1-antitrypsin Matrix Attachment Region Enhances RNA PolymeraseⅡ-dependent Transcription / 中国生物工程杂志

Eukaryotic DNA element called Matrix Attachment Regions (MARs) can function on regulating the structure and activity of chromosome. Traditional quantitation in vitro and indirect functional analysis can not always reflect MAR-involved physiological state. In order to study transcription regulation and make a try in methodism,? 1-antitrypsin MAR (?1-AT MAR) is cloned and incorporated into pEGFP-C1 vector. Non-MAR-containing and MAR-containing plasmids were then transfected into HEK-293 cells with LipofectamineTM 2000 respectively. Positive cell clones were assayed after 20 days of selection by G418. Semiquantitative RT-PCR and fluorescence microscope analysis show that this MAR has a positive effect on modulating nearby gene expression. Further, co-localization with newly CMV promoter and RNA polymeraseⅡ(RNAPⅡ) was detected by chromatin immunoprecipitation (ChIP), The PCR result demonstrates that more RNAPⅡwas recruited to the CMV promoter to initiate transcription in presence of MAR. ChIP can be used to confirm the MAR-mediated transcriptional activation and provide more reliable information than RT-PCR in real time. The technology is also providing a platform for our research in gene expression regulation.

Structural Biology of Eukaryotic Transcription:a Brief Introduction to The Nobel Prize in Chemistry 2006 / 生物化学与生物物理进展

A brief introduction to the X-ray crystallographic studies on RNA polymerase Ⅱ complexes and the enzymatic mechanisms revealed by the crystal structures.

Design and discovery of novel small-molecule inhibitor of CDK9 / 中国药理学通报

Aim To look for novel small-molecule inhibitors of CDK9 through structure-based virtual screening and biological activity determination.Methods Homology modeling of CDK9 was based on the 3-D structure of other cyclin-dependent kinase family members,and then virtual screening by DOCK(molecular docking)of database of small molecule was carried on.MTT method was used in inhibition of tumor cell growth in vitro,while Western blot was used for further study of molecular mechanisms.Results From the top 1000 compounds with the best DOCK energy score,27 compounds were selected for biological assay based on the diversity of chemical structure and functional group.12 of 27 selected compounds showed significantly inhibition activity on tumor cell proliferation,and only one compound in 12 with half-maximum inhibition concentration(IC50)values less than 20 ?mol?L-1 named C-21 was selected for further molecular mechanism study.The western blotting data showed C-21 compound could effectively inhibit CDK9 from phosphorylating large subunit C-terminal of RNA polymerase Ⅱ in a dose-dependent manner.Conclusions Through homology modeling,virtual screening by computer,determination of biological activity and experimental studies of molecular mechanism,a new promising lead compound targeted for CDK9 was found and confirmed.

Human p100 protein:a novel coactivator that enhances ST AT6-mediated gene transcriptional activation / 中国免疫学杂志

Objective:To setup a stable cell line which can overexpress human p100 protein,and then st udy the physiologic functions of p100 in regulation of STAT6-mediated gene tran scription.Methods:Using coimmunoprecipitation method to identify protein-protein interactions.STA T6-mediated gene transcriptional activation was detected by luciferase assay.Results:Human p100 protein interacted with both STAT6 and RNA polymerase Ⅱ,resulting in the enhancement of STAT6-mediated gene transcriptional activation.Conclusion:Human p100 protein acts as a bridging factor between STAT6 and basal transcripti onal machenary. [