Project description:Nuclear actin has been demonstrated to be essential for optimal transcription, but the molecular mechanisms and direct binding partner for actin in the RNA polymerase complex have remained unknown. By using purified proteins in several biochemical assays, we demonstrate a direct and specific interaction between monomeric actin and Cdk9, the kinase subunit of the positive transcription elongation factor b (P-TEFb) required for RNA polymerase II (Pol II) pause-release. This interaction is not dependent on kinase activity of Cdk9 and is not involved with releasing P-TEFb from its inhibitor 7SK snRNP complex. Supporting the specific role for actin in the elongation phase of transcription, chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) reveals that actin interacts with genes only upon their active transcription elongation. This study therefore provides novel insights into the mechanisms by which actin facilitates the transcription process.
Project description:Nuclear actin has been demonstrated to be essential for optimal transcription, but the molecular mechanisms and direct binding partner for actin in the RNA polymerase complex have remained unknown. By using purified proteins in a variety of biochemical assays, we demonstrate a direct and specific interaction between monomeric actin and Cdk9, the kinase subunit of the positive transcription elongation factor b required for RNA polymerase II pause-release. This interaction efficiently prevents actin polymerization, is not dependent on kinase activity of Cdk9, and is not involved with releasing positive transcription elongation factor b from its inhibitor 7SK snRNP complex. Supporting the specific role for actin in the elongation phase of transcription, chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) reveals that actin interacts with genes only upon their active transcription elongation. This study therefore provides novel insights into the mechanisms by which actin facilitates the transcription process.
Project description:Actin dynamically shuttles between the nucleus and cytosplasm and regulates a wide range of transcriptional processes within the nucleus We used gene expression profiling of keratinocytes overexpressing wild type actin or actin tagged with a nuclear localisation sequence to identify genes specifically regulated by nuclear actin
Project description:This study evaluated transcriptomic responses to submergence in elongating and non-elongating leaves of rice near-isogenic lines with and without SUB1A using RNA-Seq. SUB1A is an ERF transcription factor gene and the key regulator of submergence tolerance in rice, restricting underwater elongation and avoiding starvation under the stress. Submergence induces mRNA accumulation of SUB1A similarly in elongating and non-elongating leaves. This study uncovered SUB1A-dependent and independent regulation of adaptive responses to submergence in the two functionally distinct leaves at the global level.
Project description:We reasoned that the pi-RISC, by virtue of the enormous sequence portfolio of piRNAs, might mediate elimination of a large variety of mRNAs in late stages of spermiogenesis. Both Miwi-null and Caf1-null mice showed early spermiogenic arrest, preventing us from determining the role of MIWI and CAF1 in elongating spermatids using the existing genetic models. We therefore used microarrays to detail the global effect of MIWI or CAF1 on mRNA levels in mouse elongating spermatids. Using GFP+ elongating spermatids sorted from mouse testes transduced with shMiwi:GFP, shCaf1:GFP, or control pSilencer:GFP, we performed transcriptome profiling on Affymetrix mouse arrays.
Project description:RNA microarray analyses revealed that nuclear actin activated many human transcription factor genes including OCT4, which is required for gene reprogramming. OCT4 is known to be activated by nuclear actin in Xenopus oocytes. Our findings imply that this process of OCT4 activation is conserved in vertebrates and among cell types, and could be used for gene reprogramming of human cells.
Project description:Skeletal muscle actin mice (Crawford et al., (2002) Mol Cell Biol 22, 5587) were crossed with cardiac actin transgenic mice (termed "ACTC^Coco" or "Coco" for short), to produce mice that had cardiac actin instead of skeletal muscle actin in their skeletal muscles (termed "ACTC^Co/KO" or for short "Coco/KO"). Microarray analysis using the Illumina mouse-6 v1.1 expression beadchip was performed on RNA extraced from the soleus muscle of Coco/KO mice and wildtype mice, to confirm the swith in actin isoform expression, and to determine what other differences might exist between wildtype mice and the Coco/KO mice. Keywords: genetic modification 3 RNA samples (each being the pool of two individual samples extracted from different soleus muscles from different individual mice) per genotype (either wildtype or Coco/KO) were used. The total 6 RNA samples were processed using an Illumina mouse-6 v1.1expression beadchip and then the differentially expressed genes determined.