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RNA Populations (rna + population)
Selected AbstractsSpermatozoal RNAs: What about their functions?MICROSCOPY RESEARCH AND TECHNIQUE, Issue 8 2009Jean-Pierre Dadoune Abstract The profound architectural changes that transform spermatids into spermatozoa result in a high degree of DNA packaging within the sperm head. However, the mature sperm chromatin that harbors imprinted genes exhibits a dual nucleoprotamine/nucleohistone structure with DNase-sensitive regions, which could be implicated in the establishment of efficient epigenetic information in the developing embryo. Despite its apparent transcriptionally inert state, the sperm nucleus contains diverse RNA populations, mRNAs, antisense and miRNAs, that have been transcribed throughout spermatogenesis. There is also an endogenous reverse transcriptase that may be activated under certain circumstances. It is now commonly accepted that sperm can deliver some RNAs to the ovocyte at fertilization. This review presents potential links between male-specific genomic imprinting, chromatin organization, and the presence of diverse RNA populations within the sperm nucleus and discusses the functional significance of these RNAs in the spermatozoon itself and in the early embryo following fertilization. Some recent data are provided, supporting the view that analyzing the profile of spermatozoal RNAs could be useful for assessment of male fertility. Microsc. Res. Tech. 2009. © 2009 Wiley-Liss, Inc. [source] Quantitative analysis of messenger RNA abundance for ribosomal protein L-15, cyclophilin-A, phosphoglycerokinase, ,-glucuronidase, glyceraldehyde 3-phosphate dehydrogenase, ,-actin, and histone H2A during bovine oocyte maturation and early embryogenesis in vitroMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 3 2006AnilKumar Bettegowda Abstract Real-time reverse transcription PCR has greatly improved the ease and sensitivity of quantitative gene expression studies. However, measurement of gene expression generally requires selection of a valid reference (housekeeping gene) for data normalization to compensate for inherent variations. Given the dynamic nature of early embryonic development, application of this technology to studies of oocyte and early embryonic development is further complicated due to limited amounts of starting material and a paucity of information on constitutively expressed genes for data normalization. We have validated quantitative procedures for real-time reverse transcription polymerase chain reaction (RT-PCR) analysis of mRNA abundance during bovine meiotic maturation and early embryogenesis and utilized this technology to determine temporal changes in mRNA abundance for ribosomal protein L-15, cyclophilin-A, phosphoglycerokinase, ,-glucuronidase, glyceraldehyde-3-phosphate dehydrogenase, ,-actin, and histone H2A. Quantification of amounts of specific exogenous RNAs added to samples revealed acceptable rates of RNA recovery and efficiency of reverse transcription with minimal variation. Progression of bovine oocytes to metaphase II resulted in reduced abundance of polyadenylated, but not total transcripts for majority of above genes; however phosphoglycerokinase exhibited a significant decline in both RNA populations. Abundance of mRNAs for above genes in early embryos generally remained low until the blastocyst stage, but abundance of ribosomal protein L-15 mRNA was increased at the morula stage and histone H2A mRNA showed dynamic changes prior to embryonic genome activation. Results demonstrate a valid approach for quantitative analysis of mRNA abundance in oocytes and embryos, but do not support constitutive expression of above genes during early embryonic development. Mol. Reprod. Dev. © 2005 Wiley-Liss, Inc. [source] Comparison of viral RNA populations of pathogenically distinct isolates of Citrus tristeza virus : application to monitoring cross-protectionPLANT PATHOLOGY, Issue 3 2002A. Sambade The population of sequence variants of Citrus tristeza virus (CTV) isolates of different geographic origins and pathogenicity properties was characterized by single-strand conformation polymorphism (SSCP) analysis of cDNA of the genes p18, p13, p20 and p23. The mild isolates analysed here usually yielded a SSCP profile with two DNA bands, suggestive of a predominant sequence variant, whereas the SSCP profile of the most virulent isolates contained more than two DNA bands, indicating that their viral populations are likely to be more complex. The set of SSCP profiles of the four genes allowed identification of individual isolates, but no profile characteristic of a geographic area or a biogroup was found. Sweet orange plants singly inoculated with a mild or with a severe isolate yielded the SSCP profile characteristic of each isolate, whereas the SSCP profile of plants successively inoculated with both isolates was a composite of the two individual profiles. The SSCP profile of plants singly inoculated remained constant, but the profile of doubly inoculated plants varied with time. Plants in which the SSCP profile of the severe isolate became predominant showed stem pitting, and those in which the predominant profile corresponded to the mild isolate remained symptomless. The results indicate that SSCP analysis can be used to study changes in RNA populations of doubly inoculated plants and to monitor cross-protection between mild and severe isolates. [source] Low-intensity microwave irradiation does not substantially alter gene expression in late larval and adult Caenorhabditis elegansBIOELECTROMAGNETICS, Issue 8 2009Adam S. Dawe Abstract Reports that low-intensity microwave radiation induces heat-shock reporter gene expression in the nematode, Caenorhabditis elegans, have recently been reinterpreted as a subtle thermal effect caused by slight heating. This study used a microwave exposure system (1.0,GHz, 0.5,W power input; SAR 0.9,3,mW,kg,1 for 6-well plates) that minimises temperature differentials between sham and exposed conditions (,0.1 °C). Parallel measurement and simulation studies of SAR distribution within this exposure system are presented. We compared five Affymetrix gene arrays of pooled triplicate RNA populations from sham-exposed L4/adult worms against five gene arrays of pooled RNA from microwave-exposed worms (taken from the same source population in each run). No genes showed consistent expression changes across all five comparisons, and all expression changes appeared modest after normalisation (,40% up- or down-regulated). The number of statistically significant differences in gene expression (846) was less than the false-positive rate expected by chance (1131). We conclude that the pattern of gene expression in L4/adult C. elegans is substantially unaffected by low-intensity microwave radiation; the minor changes observed in this study could well be false positives. As a positive control, we compared RNA samples from N2 worms subjected to a mild heat-shock treatment (30 °C) against controls at 26 °C (two gene arrays per condition). As expected, heat-shock genes are strongly up-regulated at 30 °C, particularly an hsp -70 family member (C12C8.1) and hsp -16.2. Under these heat-shock conditions, we confirmed that an hsp -16.2::GFP transgene was strongly up-regulated, whereas two non-heat-inducible transgenes (daf- 16::GFP; cyp -34A9::GFP) showed little change in expression. Bioelectromagnetics 30:602,612, 2009. © 2009 Wiley-Liss, Inc. [source] | ||||||||||