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ABSTRACT: Codon bias is the phenomenon in which distinct synonymous codons are used with different frequencies. We define here the "codonome value" as the total number of codons present across all the expressed mRNAs in a given biological condition. We have developed the "CODONOME" software, which calculates the codon bias and, following integration with a gene expression profile, estimates the actual frequency of each codon at the transcriptome level (codonome bias) of a given tissue. Systematic analysis across different human tissues and multiple species shows a surprisingly tight correlation between the codon bias and the codonome bias. An aneuploidy and cancer condition such as that of Down Syndrome-related acute megakaryoblastic leukemia (DS-AMKL), does not appear to alter this relationship. The law of correlation between codon bias and codonome emerges as a property of the distribution and range of the number, sequence and expression level of the genes in a genome.
Genomics 03/2013; · 3.02 Impact Factor
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ABSTRACT: The "5' end mRNA artifact" issue refers to the incorrect assignment of the first AUG codon in an mRNA, due to the incomplete determination of its 5' end sequence. We performed a systematic identification of coding regions at the 5' end of all human known mRNAs, using an automated expressed sequence tag (EST)-based approach. Following parsing of more than 7 million BLAT alignments, we found 477 human loci, out of 18,665 analyzed, in which an extension of the mRNA 5' coding region was identified. Proof-of-concept confirmation was obtained by in vitro cloning and sequencing for GNB2L1, QARS and TDP2 cDNAs, and the consequences for the functional studies of these loci are discussed. We also generated a list of 20,775 human mRNAs where the presence of an in-frame stop codon upstream of the known start codon indicates completeness of the coding sequence at 5' in the current form.
Genomics 05/2012; 100(2):125-30. · 3.02 Impact Factor
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Luca Lenzi,
Federica Facchin,
Francesco Piva,
Matteo Giulietti, Maria Chiara Pelleri,
Flavia Frabetti,
Lorenza Vitale,
Raffaella Casadei,
Silvia Canaider,
Stefania Bortoluzzi,
Alessandro Coppe,
Gian Antonio Danieli,
Giovanni Principato,
Sergio Ferrari,
Pierluigi Strippoli
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ABSTRACT: Several tools have been developed to perform global gene expression profile data analysis, to search for specific chromosomal regions whose features meet defined criteria as well as to study neighbouring gene expression. However, most of these tools are tailored for a specific use in a particular context (e.g. they are species-specific, or limited to a particular data format) and they typically accept only gene lists as input.
TRAM (Transcriptome Mapper) is a new general tool that allows the simple generation and analysis of quantitative transcriptome maps, starting from any source listing gene expression values for a given gene set (e.g. expression microarrays), implemented as a relational database. It includes a parser able to assign univocal and updated gene symbols to gene identifiers from different data sources. Moreover, TRAM is able to perform intra-sample and inter-sample data normalization, including an original variant of quantile normalization (scaled quantile), useful to normalize data from platforms with highly different numbers of investigated genes. When in 'Map' mode, the software generates a quantitative representation of the transcriptome of a sample (or of a pool of samples) and identifies if segments of defined lengths are over/under-expressed compared to the desired threshold. When in 'Cluster' mode, the software searches for a set of over/under-expressed consecutive genes. Statistical significance for all results is calculated with respect to genes localized on the same chromosome or to all genome genes. Transcriptome maps, showing differential expression between two sample groups, relative to two different biological conditions, may be easily generated. We present the results of a biological model test, based on a meta-analysis comparison between a sample pool of human CD34+ hematopoietic progenitor cells and a sample pool of megakaryocytic cells. Biologically relevant chromosomal segments and gene clusters with differential expression during the differentiation toward megakaryocyte were identified.
TRAM is designed to create, and statistically analyze, quantitative transcriptome maps, based on gene expression data from multiple sources. The release includes FileMaker Pro database management runtime application and it is freely available at http://apollo11.isto.unibo.it/software/, along with preconfigured implementations for mapping of human, mouse and zebrafish transcriptomes.
BMC Genomics 02/2011; 12:121. · 4.07 Impact Factor
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ABSTRACT: Human RCAN3 (regulator of calcineurin 3) belongs to the human RCAN gene family.In this study we provide, with in silico and in vitro analyses, the first detailed description of the human multi-transcript RCAN3 locus. Its analysis revealed that it is composed of a multigene system that includes at least 21 RCAN3 alternative spliced isoforms (16 of them identified here for the first time) and a new RCAN3 antisense gene (RCAN3AS). In particular, we cloned RCAN3-1,3,4,5 (lacking exon 2), RCAN3-1a,2,3,4,5, RCAN3-1a,3,4,5, RCAN3-1b,2,3,4,5, RCAN3-1c,2,3,4,5, RCAN3-1c,2,4,5 and RCAN3-1c,3,4,5, isoforms that present a different 5' untranslated region when compared to RCAN3. Moreover, in order to verify the possible 5' incompleteness of previously identified cDNA isoforms with the reference exon 1, ten more alternative isoforms were retrieved. Bioinformatic searches allowed us to identify RCAN3AS, which overlaps in part with exon 1a, on the opposite strand, for which four different RCAN3AS isoforms were cloned.In order to analyze the different expression patterns of RCAN3 alternative first exons and of RCAN3AS mRNA isoforms, RT-PCR was performed in 17 human tissues. Finally, analyses of RCAN3 and RCAN3AS genomic sequences were performed to identify possible promoter regions, to examine donor and acceptor splice sequences and to compare evolutionary conservation, in particular of alternative exon 1 or 1c--exon 2 junctions in different species.The description of its number of transcripts, of their expression patterns and of their regulatory regions can be important to clarify the functions of RCAN3 gene in different pathways and cellular processes.
PLoS ONE 01/2011; 6(9):e24508. · 4.09 Impact Factor
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ABSTRACT: Housekeeping (HK) genes are constitutively expressed in order to maintain cellular function. They produce the minimal essential transcripts necessary for normal cellular physiology. Wide range expression, stable expression level and high expression level are independent features of a single gene expression and are all desirable for the definition of an "ideal" HK. Recent studies have questioned the possible existence of "ideal" HK mRNAs, mainly because of the wide expression conditions variability. This would imply that for each investigated organism the suitability of a putative HK should be verified. We perform a systematic analysis to identify "optimal" HK genes in Danio rerio (zebrafish), to be used in expression analyses conducted on embryos/larvae at different developmental stages, as well as on differentiated adult tissues from single donors. The expression pattern of candidate genes, selected on the basis of the literature available and of ad hoc bioinformatics analysis, was assessed by quantitative relative RT-PCR in an RNA panel, including six different embryo/larvae developmental stages and six adult tissues. Statistical analysis was performed to identify genes with the lowest expression standard deviation in the studied panel. Our results showed that beta-actin 2 (bactin2) is the mRNA with the lowest variability of expression.
Gene Expression Patterns 01/2011; 11(3-4):271-6. · 2.02 Impact Factor
