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    Michio Kaku Explains Massive Sunspot 1302 Has Earth in its Sites. eric1970x 80 videos. Subscribe Alert icon Subscribed. Sign In or Sign Up
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    MicroRNAs (miRNAs) and copy number variations (CNVs) are two newly discovered genetic elements that have revolutionized the field of molecular biology and genetics. By performing in silico whole genome analysis, we demonstrate that both the number of miRNAs that target genes found in CNV regions as well as the number of miRNA-binding sites are significantly higher than those of genes found in non-CNV regions. This suggests that miRNAs may have acted as equilibrators of gene expression during evolution in an attempt to regulate aberrant gene expression and to increase the tolerance to genome plasticity.
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    Serum response factor (SRF) and myocyte enhancer factor 2 (MEF2) represent two types of members of the MCM1, AGAMOUS, DEFICIENS, and SRF (MADS)-box transcription factor family present in animals and fungi. Each type has distinct biological functions, which are reflected by the distinct specificities of the proteins bound to their cognate DNA-binding sites and activated by their respective cofactors. However, little is known about the evolution of MADS domains and their DNA-binding sites. Here, we report on the conservation and evolution of the two types of MADS domains with their cognate DNA-binding sites by using phylogenetic analyses. First, there are great similarities between the two types of proteins with amino acid positions highly conserved, which are critical for binding to the DNA sequence and for the maintenance of the 3D structure. Second, in contrast to MEF2-type MADS domains, distinct conserved residues are present at some positions in SRF-type MADS domains, determining specificity and the configuration of the MADS domain bound to DNA sequences. Furthermore, the ancestor sequence of SRF- and MEF2-type MADS domains is more similar to MEF2-type MADS domains than to SRF-type MADS domains. In the case of DNA-binding sites, the MEF2 site has a T-rich core in one DNA sequence and an A-rich core in the reverse sequence as compared with the SRF site, no matter whether where either A or T is present in the two complementary sequences. In addition, comparing SRF sites in the human and the mouse genomes reveals that the evolution rate of CArG-boxes is faster in mouse than in human. Moreover, interestingly, a CArG-like sequence, which is probably functionless, could potentially mutate to a functional CArG-box that can be bound by SRF and vice versa. Together, these results significantly improve our knowledge on the conservation and evolution of the MADS domains and their binding sites to date and provide new insights to investigate the MADS family, which is not only on evolution of MADS factors but also on evolution of their binding sites and even on coevolution of MADS factors with their binding sites.
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    If you are looking for Fossil Hunting Sites and Resources In The USA this is the page you are looking for.
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