Transcription profiling of T. brucei trypanosomes during differentiation reveals the existence of multiple post-transcriptional regulons.
ABSTRACT: We analysed differentiation of the EATRO1125 strain of Trypanosoma brucei brucei, which was first isolated in 1966 from a bushbuck (Tragelaphus scriptus) in Uganda (origin stated (Bouteillea, 1995) without an original reference. To analyse gene expression, we isolated at least 3 x 10e8 trypanosomes at different differentiation states, using two independent biological replicates. Bloodstream forms were harvested at a density of 2 x 10e5/ml (low density, logarithmic growth), and 2 x 10e6/ml (high density, logarithmic growth). Cells were also taken immediately upon attaining the density of 2 x 106/ml, treated with 3 mM cis-aconitate and moved to a room at 27°C. Samples were taken 30 min, 60 min, 12h and 24h after this. At 24 h the cells were centrifuged, resuspended (at 27°C) in MEM-Pros medium, which contains proline as the major energy source. Samples were taken again at 48h and 72h. A culture that had been maintained for several weeks after transformation was used as a source of established procyclic trypanosomes.
Project description:Cy3 and Cy5 direct labelled RNA from Bloodstream MiTat1.1 trypanosomes and Procyclic 427 Lister were hybridized onto JCVI Trypanosoma brucei oligoarrays (version2). Procyclic RNA were used as control for data analysis.
Project description:Investigation of transcription profile of spontaneous Cefotaxime resistant R6 mutants containing mutations in pbp2x, ciaH, pbp2a and mutants with different mosaic pbp2x, pbp1a genes.
Project description:We mapped the transcriptional regulatory circuitry for six master regulators in human hepatocytes using chromatin immunoprecipitation and high-resolution promoter microarrays. The results show that these regulators form a highly interconnected core circuitry, and reveal the local regulatory network motifs created by regulator-gene interactions. Auto-regulation was a prominent theme among these regulators. We found that hepatocyte master regulators tend to bind promoter regions combinatorially and that the number of transcription factors bound to a promoter corresponds with observed gene expression. Our studies reveal portions of the core circuitry of human hepatocytes.
Project description:Procyclic trypanosomes (strain 427 lister) were grown in culture under standard conditions at 27ºC in SDM79 medium with 10% foetal bovine serume (Brun and Schnenberger, 1979), in a gazed incubator (5% CO2). Logarithmically growing procyclic cells (at about 5*10^6 cells/ml, at 27°C) were added to one volume medium that had been heated to 53°C and incubated at 41ºC for 60 minutes in a waterbath in a closed tube (41ºC sample). The control cells were added to one volume medium at 27ºC and also incubated for 60 minutes in a closed tube at 27°C. Cells were harvested and washed once in PBS. The harvesting was done within 8 minutes.
Project description:Purpose: Ribosome profiling and RNA-Seq were used to map the location and abundance of translating ribosomes on human skeletal muscle transcripts from a patient with Becker muscular dystrophy. Methods: Tissue homogenates were prepared from frozen sections of a muscle biopsy obtained from a patient with an NM_004006:c.40_41delGA dystrophin mutation and a normal control. Ribosome-protected fragments and total RNA were prepared from a single homogenate, so starting RNA populations for both libraries were closely matched. Homogenates were not clarified before RNase digestion to avoid loss of ribosomes associated with large molecular weight complexes and RNA-Seq libraries were prepared after rRNA subtraction to avoid positional loss of 5’ reads. RPF-Seq libraries were built using the TruSeq Small RNA Sample Preparation Kit (Illumina) and RNA-Seq libraries were built using the TruSeq RNA Sample Preparation v2 Kit (Illumina). RPF-Seq and RNA-Seq libraries were subjected to 50 cycles of single-end sequencing on an Illumina HiSeq 2000 instrument. Trimmed and filtered RPF- and RNA-Seq reads were mapped to RefSeq fasta sequences downloaded from the UCSC genome browser (hg19 assembly). Results: Most mutations that truncate the reading frame of the DMD gene result in loss of dystrophin expression and lead to Duchenne muscular dystrophy. However, amelioration of disease severity can result from alternate translation initiation beginning in DMD exon 6 that results in the expression of a highly functional N-truncated dystrophin. This novel isoform results from usage of an internal ribosome entry site (IRES) within exon 5 that is glucocorticoid-inducible. IRES activity is confirmed in patient muscle by both peptide sequencing and ribosomal profiling. Conclusions: Our results provide a molecular explanation for the rescue of 5’ truncating mutations via a heretofore undescribed mechanism of post-transcriptional regulation of dystrophin expression. The presence of a glucocorticoid-inducible IRES within a highly conserved region of the DMD sequence strongly suggests a programmed role for alternate translation initiation, and ongoing efforts to understand the relevant cell lineage-specific and/or conditional activation signals will shed light on underlying mechanisms of IRES control and elucidate potentially novel functions of dystrophin. Skeletal muscle ribosome-protected fragment and RNA-Seq profiles from a patient with an NM_004006:c.40_41delGA dystrophin mutation and a normal control were generated by deep sequencing using the Illumina HiSeq 2000.
Project description:Mature green fruits of the tomato (Solanum lycopersicum L.) cultivar MicroTom were investigated (fruit developmental category II). After harvest, fruits were immediately utilized or stored in darkness at 25 C until further processing. After 0, 1, 2 or 4 days of storage stem scar tissues of tomato fruits were excised with a scalpel to a depth of approximately 2 mm, immediately frozen in liquid nitrogen and stored at -80 C until use.
Project description:Inhibition of cellulose synthesis by chemical inhibitors or in a mutant background leads to rapid inhibition of cell elongation. This inhibition appears to be an active process, which involves feedback signalling from the cell wall. We have isolated two loci THE1 and THE2, which are identified by mutations that partially suppress the dark-grown hypocotyl phenotype in a mutant background for cellulose synthase catalytic subunit CESA6_PROCUSTE1. THE1 encodes a receptor kinase and may play a role in this feedback signalling process. To identify genes that are regulated by THE1 and THE2, we compared the transcript profiles of 5 day-old dark-grown seedlings of the1-1_prc1-1 with prc1-1 ; the1-3_prc1-8 with prc1-8 ; prc1-8 or the1-3 with WS and the2-1_prc1-1 with prc1-1.