Project description:Intragenic microRNAs (miRNAs), including both intronic and exonic miRNAs, accounting approximately 50% of total mammalian miRNAs. Previous studies showed that intragenic miRNAs are often co-expressed with their host genes, and thus it was believed that intragenic miRNAs and their host genes are derived from the same primary transcripts. However, we provide evidence to show here that the observations from previous studies might be biased due to the small number and the predominance of "broadly conserved" intronic miRNAs they studied. We analyzed expression correlation of hundreds intragenic miRNAs with their host genes in two human and one mouse sample sets resulting from genome-wide miRNA arrays and exon arrays. We found that on average over 60% of intragenic miRNAs might not be co-expressed with their host genes. We show that evolution conservation is the most important factor related to the probability of co-expression of intragenic miRNAs with host genes, and the greater conservation degree of intragenic miRNAs is associated with the higher co-expression rate. Surprisingly, exonic miRNAs have a much lower rate of coexpression with host genes than intronic miRNAs, and 80% of them likely do not share primary transcripts with overlapping exons in biogenesis. Although "broadly conserved" intronic miRNAs have much shorter introns and a higher co-expression rate than (less broadly) "conserved" or "poorly conserved" ones, there is no consistently significant link between host intron size and co-expression probability of intronic miRNAs. In sum, our data suggest that the majority of intragenic miRNAs might be transcribed independently from their host genes. We used microRNA array and exon array to get the correlation between miRNA and mRNA in different datasets: 81 human leukemia samples and 14 mouse es-eb samples. In this study, we analyzed 26 mouse samples using the Affymetrix Mouse Exon 1.0 ST platform. Array data was processed by Affymetrix Expression Console. No techinical replicates were performed.

Project description:MicroRNAs (miRNAs) are small non-coding RNAs found to regulate several biological processes including adipogenesis. Understanding adipose tissue regulation is critical for beef cattle as fat is an important determinant of beef quality and nutrient value . This study analyzed the association between genomic context characteristics of miRNAs with their expression and function in bovine adipose tissue. Twenty-four subcutaneous adipose tissue biopsies were obtained from eight British-continental crossbred steers at 3 different time points . Total RNA was extracted and miRNAs were profiled using a miRNA microarray with expression further validated by qRT-PCR. A total of 224 miRNAs were detected of which 155 were expressed in all steers (n=8), and defined as the core miRNAs of bovine subcutaneous adipose tissue. Core adipose miRNAs varied in terms of genomic location (59.5% intergenic, 38.7% intronic, 1.2% exonic, and 0.6% mirtron), organization (55.5% non-clustered and 44.5% clustered), and conservation (49% highly conserved, 14% conserved and 37% poorly conserved). Clustered miRNAs and highly conserved miRNAs were more highly expressed (p<0.05) and had more predicted targets than non-clustered or less conserved miRNAs (p<0.001). A total of 34 miRNAs were coordinately expressed, being part of six identified relevant networks. Two intronic miRNAs (miR-33a and miR-1281) were shown to have coordinated expression with their host genes which are involved in lipid metabolism, suggesting these miRNAs may also play a role in regulation of lipid metabolism/adipogenesis of bovine adipose tissue. Furthermore, a total of 17 bovine specific miRNAs were predicted to be involved in the regulation of energy balance in adipose tissue. These findings improve our understanding on the behavior of miRNAs in the regulation of bovine adipogenesis and fat metabolism as it reveals that miRNA expression patterns and functions are associated with miRNA genomic organization and conservation in bovine adipose tissue. In this study, a total of 24 subcutaneous adipose tissue samples were analyzed by microRNA microarrays. The samples were derived from eight steers at three different ages (12, 13.5 and 15 months).

Project description:MicroRNAs (miRNAs) are small non-coding RNAs found to regulate several biological processes including adipogenesis. Understanding adipose tissue regulation is critical for beef cattle as fat is an important determinant of beef quality and nutrient value . This study analyzed the association between genomic context characteristics of miRNAs with their expression and function in bovine adipose tissue. Twenty-four subcutaneous adipose tissue biopsies were obtained from eight British-continental crossbred steers at 3 different time points . Total RNA was extracted and miRNAs were profiled using a miRNA microarray with expression further validated by qRT-PCR. A total of 224 miRNAs were detected of which 155 were expressed in all steers (n=8), and defined as the core miRNAs of bovine subcutaneous adipose tissue. Core adipose miRNAs varied in terms of genomic location (59.5% intergenic, 38.7% intronic, 1.2% exonic, and 0.6% mirtron), organization (55.5% non-clustered and 44.5% clustered), and conservation (49% highly conserved, 14% conserved and 37% poorly conserved). Clustered miRNAs and highly conserved miRNAs were more highly expressed (p<0.05) and had more predicted targets than non-clustered or less conserved miRNAs (p<0.001). A total of 34 miRNAs were coordinately expressed, being part of six identified relevant networks. Two intronic miRNAs (miR-33a and miR-1281) were shown to have coordinated expression with their host genes which are involved in lipid metabolism, suggesting these miRNAs may also play a role in regulation of lipid metabolism/adipogenesis of bovine adipose tissue. Furthermore, a total of 17 bovine specific miRNAs were predicted to be involved in the regulation of energy balance in adipose tissue. These findings improve our understanding on the behavior of miRNAs in the regulation of bovine adipogenesis and fat metabolism as it reveals that miRNA expression patterns and functions are associated with miRNA genomic organization and conservation in bovine adipose tissue.

Dataset Information

81 human leukemia samples (affymetrix exon array)

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