Tay Y, Zhang J, Thomson AM, Lim B, Rigoutsos IMicroRNAs to Nanog, Oct4 and Sox2 coding regions modulate embryonic stem cell differentiation. Nature 455: 1124-1128
Stem Cell and Developmental Biology, Genome Institute of Singapore, Agency for Science Technology and Research, #08-01, Genome, 60 Biopolis Street, Singapore 138672, Singapore. Nature
(Impact Factor: 41.46).
10/2008; 455(7216):1124-8. DOI: 10.1038/nature07299
MicroRNAs (miRNAs) are short RNAs that direct messenger RNA degradation or disrupt mRNA translation in a sequence-dependent manner. For more than a decade, attempts to study the interaction of miRNAs with their targets were confined to the 3' untranslated regions of mRNAs, fuelling an underlying assumption that these regions are the principal recipients of miRNA activity. Here we focus on the mouse Nanog, Oct4 (also known as Pou5f1) and Sox2 genes and demonstrate the existence of many naturally occurring miRNA targets in their amino acid coding sequence (CDS). Some of the mouse targets analysed do not contain the miRNA seed, whereas others span exon-exon junctions or are not conserved in the human and rhesus genomes. miR-134, miR-296 and miR-470, upregulated on retinoic-acid-induced differentiation of mouse embryonic stem cells, target the CDS of each transcription factor in various combinations, leading to transcriptional and morphological changes characteristic of differentiating mouse embryonic stem cells, and resulting in a new phenotype. Silent mutations at the predicted targets abolish miRNA activity, prevent the downregulation of the corresponding genes and delay the induced phenotype. Our findings demonstrate the abundance of CDS-located miRNA targets, some of which can be species-specific, and support an augmented model whereby animal miRNAs exercise their control on mRNAs through targets that can reside beyond the 3' untranslated region.
Available from: Vivek Tanavde
- "While some of these candidates will have a decreased ribosomal load due to a decreased ORF length it is likely that the remaining transcripts contain cisacting regulatory sequences within their ORF. miRNAs have been shown to target the ORF of mRNAs[40,41]so it is possible that the changes in ORF seen in these variants results in altered translational control in addition to altered protein function. Exon 4 and 5 in Ctage5 variant 1 are associated with a decreased ribosomal load compared to variant 3 that skips these exons. "
[Show abstract] [Hide abstract]
ABSTRACT: The presence of multiple variants for many mRNAs is a major contributor to protein diversity. The processing of these variants is tightly controlled in a cell-type specific manner and has a significant impact on gene expression control. Here we investigate the differential translation rates of individual mRNA variants in embryonic stem cells (ESCs) and in ESC derived Neural Precursor Cells (NPCs) using polysome profiling coupled to RNA sequencing. We show that there are a significant number of detectable mRNA variants in ESCs and NPCs and that many of them show variant specific translation rates. This is correlated with differences in the UTRs of the variants with the 5'UTR playing a predominant role. We suggest that mRNA variants that contain alternate UTRs are under different post-transcriptional controls. This is likely due to the presence or absence of miRNA and protein binding sites that regulate translation rate. This highlights the importance of addressing translation rate when using mRNA levels as a read out of protein abundance. Additional analysis shows that many annotated non-coding mRNAs are present on the polysome fractions in ESCs and NPCs. We believe that the use of polysome fractionation coupled to RNA sequencing is a useful method for analysis of the translation state of many different RNAs in the cell.
Available from: Seyed Javad Mowla
- "MiR-134 is reported to be involved in cortical neural development and memory formation (Gao et al., 2010; Gaughwin et al., 2011). Considered as a powerful inducer of embryonic stem cells differentiation , miR-134 could promote cellular proliferation and counteract apoptosis in neural progenitor cells (Tay et al., 2008; Gaughwin et al., 2011; Poitz et al., 2013). According to the previous reports, miR-134 is upregulated in developing lung and modulates cell proliferation, apoptosis, and migration during lung septation (Williams et al., 2007; Zhang et al., 2012). "
[Show abstract] [Hide abstract]
MicroRNAs (miRNAs) are involved in various cellular events needed for embryonic development and tumorigenesis. As some of the development-specific gene expression patterns could be observed in cancers, we speculated that the expression pattern of lung development-specific miRNAs miR-134 and miR-187 might be altered in lung tumor samples. Lung cancer is the first cause of cancer related deaths worldwide, mostly due to its late diagnosis. Therefore, finding a reliable diagnostic tumor marker, based on molecular profile of tumorigenesis, would be critical in lowering lung cancer mortality.
We employed a real-time RT-PCR approach to evaluate the expression alteration of two lung development-related miRNAs in lung tumor tissues. The suitability of miRs expression alterations as lung tumor biomarkers was tested by receiver operating characteristic (ROC) curve analysis. The effect of miR-187 overexpression on a lung carcinoma cell cycle was assessed using flow cytometry analysis.
Our data revealed a significant upregulation (7.8 times, p<0.02) of miR-134 in lung tumors. However, its expression level failed to discriminate different tumor types and grades of malignancies from each other. Moreover, the ROC curves analysis did not give it a good score as a reliable biomarker (AUC=0.522, P=0.729). In contrast, miR-187 showed a significant down-regulation (P=0.008) in lung tumors. Similarly, its expression level failed to differentiate different tumor types or grades of malignancies. Nevertheless, ROC curve analysis gave it an AUC score of 0.669 (P=0.012), which suggests its suitability as a potential biomarker for lung cancer. Furthermore, ectopic expression of miR-187 in A549 cells caused a cell cycle arrest in G1 phase (P=0.013).
Altogether, our data demonstrated an altered expression of two development-related miRNAs namely miR-134 and miR-187 in lung tumors for the first time. Moreover we have shown that miR-134 and miR-187 expression alternation were in accordance with their approved regulatory roles, therefore these miRNAs could serve as new biomarkers with potential usefulness in lung cancer diagnosis and treatments. In addition, miR-187 expression in tumor cells could perturb cell cycle which supported its possible role as tumor suppressor.
Available from: Azadeh Anbarlou
- "One of the important factors involved in self-renewal and maintenance of HSCs multipotency of CD34 stem cells is Sall4 transcription factor (TF) (Aguila et al., 2011). Sall4 is zinc-finger TF belong to spalt-1ike protein family, located on chromosome 20 and expressed in undifferentiated stem cells like normally embryonic stem cells (ESCs) and CD34 + HSCs (Tay et al., 2008). Sall4 binds to regulatory regions of ESCs master regulators such as Nanog and Oct-4 and regulates their expression (Wu et al., 2006; Zhang et al., 2006; Tan et al., 2013). "
[Show abstract] [Hide abstract]
ABSTRACT: Hematopoietic Stem Cells (HSCs) are cells that have the ability to self-renewal and differentiate into all of hematopoietic lineages. The lack of donors and unavailable efficient protocols for ex vivo expansion of HSCs, are obstacles in successful cell therapies. MicroRNAs (also refer as miRNAs or miRs) have significant roles in hematopoiesis; they can effect on HSCs expansion, maintaining undifferentiated state, self-renewal and differentiation. Recently attentions have been given to these small regulatory molecules to utilize them in order to expand HSCs. Using bioinformatics analysis we identified Sall4 as putative target of miR-15b and miR-219-5p. Relative expression levels of miRNAs and Sall4 were evaluated by qRT-PCR. Here we show 247-fold and 4.2fold increasing Sall4 expression level compared to control group in CD34+ cells nucleofected by anti-miR-15b and anti-miR-219-5p, respectively. These data showed that anti-miR-15b can promote clonogenic capacity of HSCs and also we found that miR-15b alone was able to increase the number of CD34+HSCs in vitro by more than 2 fold by targeting Sall4. Moreover, level of CD34 marker in HSCs nucleofected by anti-miR-15b increased more than 50%. Our analysis showed no statistically difference in mRNA level of Sall4 after nucleofection of anti-miR-219-5p. Sall4 is a factor capable of enhancing HSC expansion significantly. We demonstrated that inhibition of miR-15b can enhance ex vivo expansion of UCB-derived HSCs and also expression of Sall4 allowed expansion and preserve self- renewal of CD34+ HSCs. © 2015, Leibniz Research Centre for Working Environment and Human Factors. All rights reserved.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.