Characterization of the ovine ribosomal protein SA gene and its pseudogenes

Differentially expressed proteins in the intestine of Cynoglossus semilaevis Günther following a Shewanella algae challenge

Fish intestine is an important constituent of the mucosal immune system. The gut and gut-associated lymphoid tissue construct a local immune environment. A Shewanella algae strain was previously reported to be a pathogen causing ascitic disease accompanied with intestinal inflammation in Cynoglossus semilaevis. This study aimed to investigate the intestine immune response in C. semilaevis to S. algae infection at the protein level. Two-dimensional electrophoresis coupled with mass spectrometry proteomics was utilized to compare protein expression in the intestines from normal and S. algae-infected C. semilaevis. A total of 70 differentially expressed proteins (DEPs), consisting of 16 upregulated and 54 downregulated proteins, were identified in the intestine tissue of C. Semilaevis. These protein expression changes were further validated using western blot analysis and quantitative real-time PCR. Gene ontology enrichment analysis showed that these 70 DEPs could be assigned across three categories: "cellular components", "molecular function", and "biological process". Forty-one DEPs (six up-regulated and 35 down-regulated proteins) related to metabolic processes were identified. In addition, 20 DEPs (eight up-regulated and 12 down-regulated proteins) related to stress and immune responses were identified. A protein-protein interaction network generated by the STRING (Search Tool for the Retrieval of Interacting Genes/protein) revealed that 30 DEPs interacted with one another to form an integrated network. Among them, 29 DEPs were related to stress, immune, and metabolism processes. In the network, some of the immune related proteins (C9, FGB, KNG1, apolipoprotein A-IV-like, and PDIA3) were up-regulated and most DEPs involved in metabolism processes were down-regulated. These results indicate that the immune defense response of the intestine was activated and the intestinal function associated with metabolism processes was disturbed. This study provides valuable information for further research into the functions of these DEPs in fish.

Methods for detecting transcribed pseudogenes: PCR on regions of high sequence similarity followed by cloning and sequencing

Identifying pseudogene transcription is problematic in many cases due to the high sequence similarity between pseudogenes and their parental genes. In this chapter, we detail the procedure for the detection of pseudogene transcription using the reverse transcription polymerase chain reaction (RT-PCR) method. The protocol comprises (1) extraction of total RNA, (2) first-strand cDNA synthesis from total RNA, (3) amplification of the cDNA by PCR, and (4) cloning and sequencing of the PCR products. Technical and practical guidance is provided, and the critical points during each of the steps are discussed. In particular, the importance of designing high specific PCR primers and thoroughly eliminating genomic DNA contamination from RNA preparation is emphasized.

Comparative proteomics analysis of host cells infected with Brucella abortus A19

We carried out a proteomic analysis of THP-1-derived macrophages with and without Brucella abortus A19 (B. abortus A19) infection in order to study the cellular responses to B. abortus A19. The proteins were analyzed at different time points after infection with 2DE followed by MALDI-TOF/TOF identification. Comparative analysis of multiple 2DE gels revealed that the majority of changes in protein abundance appeared between 48 and 96 h after infection. MS identified 44 altered proteins, including 20 proteins increased in abundance and 24 proteins decreased in abundance, which were found to be involved in cytoskeleton, signal transduction, energy metabolism, host macromolecular biosynthesis, and stress response. Moreover, 22 genes corresponding to the altered proteins were quantified by real-time RT-PCR to examine the transcriptional profiles between infected and uninfected THP-1-derived macrophages. Finally, we mapped the altered pathways and networks using ingenuity pathway analysis, which suggested that the altered protein species were heavily favored germ cell-Sertoli cell junction signaling as the primary pathway. Furthermore, mechanisms of viral exit from host cell and macrophage stimulating protein-recepteur d'origine nantais signaling appeared to be major pathways modulated in infected cells. This study effectively provides useful dynamic protein-related information concerning B. abortus infection in macrophages.

Novel polysome messages and changes in translational activity appear after induction of adipogenesis in 3T3-L1 cells

Background

Control of translation allows for rapid adaptation of the cell to stimuli, rather than the slower transcriptional control. We presume that translational control is an essential process in the control of adipogenesis, especially in the first hours after hormonal stimulation. 3T3-L1 preadipocytes were cultured to confluency and adipogenesis was induced by standard protocols using a hormonal cocktail. Cells were harvested before and 6 hours after hormonal induction. mRNAs attached to ribosomes (polysomal mRNAs) were separated from unbound mRNAs by velocity sedimentation. Pools of polysomal and unbound mRNA fractions were analyzed by microarray analysis. Changes in relative abundance in unbound and polysomal mRNA pools were calculated to detect putative changes in translational activity. Changes of expression levels of selected genes were verified by qPCR and Western blotting.

Results

We identified 43 genes that shifted towards the polysomal fraction (up-regulated) and 2 genes that shifted towards free mRNA fraction (down-regulated). Interestingly, we found Ghrelin to be down-regulated. Up-regulated genes comprise factors that are nucleic acid binding (eIF4B, HSF1, IRF6, MYC, POLR2a, RPL18, RPL27a, RPL6, RPL7a, RPS18, RPSa, TSC22d3), form part of ribosomes (RPL18, RPL27a, RPL6, RPL7a, RPS18, RPSa), act on the regulation of translation (eIF4B) or transcription (HSF1, IRF6, MYC, TSC22d3). Others act as chaperones (BAG3, HSPA8, HSP90ab1) or in other metabolic or signals transducing processes.

Conclusions

We conclude that a moderate reorganisation of the functionality of the ribosomal machinery and translational activity are very important steps for growth and gene expression control in the initial phase of adipogenesis.

Molecular characterization of the full-length coding sequence of the caprine laminin receptor gene (RPSA)

Scrapie is a prion disease in sheep and goats. Ribosomal protein SA (RPSA), also called 37 kDa laminin receptor precursor/67 kDa laminin receptor has been demonstrated to be a putative cell surface receptor for prion. To investigate the caprine RPSA, we cloned the full-length coding sequence of the gene of goat and submitted it to GenBank. The length of the open reading frame is 888 bp, encoding 295 amino acids. The putative amino acid sequence is highly similar to that of other mammals. The caprine amino acid sequence of RPSA is shown to be identical to the sequence of species susceptible to scrapie at positions 241, 272, and 291. The phylogenetic tree analysis revealed that the genetic distance between sheep and goat is the smallest. Moreover, RT-PCR results of 11 tissues indicated that RPSA mRNA is expressed in all selected caprine tissues.