This Article Abstract Full Text Full Text (PDF) Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Dainiak, N Articles by Albanese, J Search for Related Content PubMed PubMed Citation Articles by Dainiak, N Articles by Albanese, J

The search for mRNA biomarkers: global quantification of transcriptional and translational responses to ionising radiation

¹ Bridgeport Hospital, Bridgeport, and Yale University School of Medicine, New Haven, CT, USA, ² Chemical Computing Group, Montreal, Quebec, Canada and ³ Yale New Haven Health System Center for Emergency Preparedness and Disaster Response, New Haven, CT, USA

View larger version (23K): [in a new window]   Figure 1. Cellular response to ionising radiation (IR)-induced DNA damage. In response to IR-induced DNA lesions, DNA sensor proteins convey DNA damage signals to transducer molecules through phosphorylation. In turn, transducer proteins activate effector molecules that are responsible for modulating cell cycle progression, DNA repair and apoptosis. Modified from Belli et al [10] with permission.

View larger version (20K): [in a new window]   Figure 2. Ionising radiation induces the expression of Fas ligand (Fas L) on the cell surface. Plasma membranes were purified from control and irradiated (4 Gy or 10 Gy) colorectal carcinoma cells (SW620) and subjected to Western blot analysis for FasL (TNFSF6) protein (panel A). mRNA for FasL was assessed by reverse transcriptase polymerase chain reaction (RT-PCR) (panel B). Whole cells (2 x 105) were treated with 0 Gy, 4 Gy or 10 Gy, sequentially labelled with rabbit anti-FasL antibody and fluorescein-conjugated anti-rabbit IgG, and analysed by flow cytometry (panel C). Note that both protein and message levels are increased in a dose-dependent manner. Reproduced from Albanese and Dainiak [28] with permission.

View larger version (21K): [in a new window]   Figure 3. Ionising radiation (IR)-induced transcription of pro-apoptotic receptor mRNAs. Sublethal doses of IR induce upregulation of mRNA coding for "death" receptors (Fas, DR4, DR5). The gene products accumulate at the cell surface where their encounter with death ligand (Fas ligand and TRAIL) triggers the assembly of cytoplastic proteins (FADD and pro-caspase 8) at the plasma membrane, leading to the activation of caspase-8 and caspase-3, with subsequent apoptosis.

View larger version (16K): [in a new window]   Figure 4. Tissue-specific gene expression. Venn diagram showing the number of genes expressed at elevated levels in various mouse tissues harvested 24 h following irradiation with 2 Gy (panel A) or 0.2 Gy (panel B) -rays. The samples were hybridised to microarrays of 4105 murine cDNAs. Note that although a small number of genes responded in all tissues examined, the majority were specific to one tissue. Reproduced from Amundson et al [36] with permission.

View larger version (49K): [in a new window]   Figure 5. - and -forms of radiation activate common genes as well as different classes of genes specific to each form of radiation. The Venn diagram in the centre shows the numbers of genes overexpressed by 2-fold or 5-fold after -irradiation, and by 4-fold after -irradiation. Pie charts show the distribution of genes that are overexpressed by 2-fold after either - or -irradiation (A), -irradiation (B) or -irradiation (C). Reproduced from Marko et al [42] with permission.

View larger version (12K): [in a new window]   Figure 6. Projection pursuit (PP). The first principal component (PC1) is rotated to an optimal separation of two groups of data points, thereby defining the first PP. From a random starting plane, two candidate planes are generated. The projection index is evaluated, using the method of Posse, to find the optimal PP index. The plane containing the best PP index is then selected as a new starting plane and the PP axes are identified from projection onto the two best planes.

View larger version (27K): [in a new window]   Figure 7. Schematic representation of an antibody microarray system for monitoring protein profiles. Equal quantities of protein from test and reference cell lysates are labelled with either Cy3- (green) or Cy5- (red) NHS dyes. Unreacted dyes are removed by size exclusion chromatography. The proteins are loaded onto an antibody microarray and the microarray is analysed using a microarray scanner. Proteins are classified as upregulated, downregulated or unchanged, according to the colour intensity ratio of the two dyes. Reproduced from Sreekumar et al [52] with permission.