microRNAs in a multicellular green alga Volvox carteri

Abstract

microRNAs (miRNAs) have emerged as key components in the eukaryotic gene regulatory network. We and others have previously identified many miRNAs in a unicellular green alga, Chlamydomonas reinhardtii. To investigate whether mi-RNA-mediated gene regulation is a general mechanism in green algae and how miRNAs have been evolved in the green algal lineage, we examined small RNAs in Volvox carteri, a multicellular species in the same family with Chlamydomonas reinhardtii. We identified 174 miRNAs in Volvox, with many of them being highly enriched in gonidia or somatic cells. The targets of the miRNAs were predicted and many of them were subjected to miRNA-mediated cleavage in vivo, suggesting that miRNAs play regulatory roles in the biology of green algae. Our catalog of miRNAs and their targets provides a resource for further studies on the evolution, biological functions, and genomic properties of miRNAs in green algae.Volvox, small RNA, microRNA, conservation, evolution Citation:Li JR, Wu Y, Qi YJ. microRNAs in a multicellular green alga Volvox carter.

Gene silencing in microalgae: Mechanisms and biological roles

“…This also appears to be the case for some miRNAs in both C. reinhardtii and V. carteri, where expected target RNA cleavage products have been experimentally detected (Molnar et al, 2007;Zhao et al, 2007;Li et al, 2014;Voshall et al, 2014). Yet, very few of the reported Chlamydomonas or Volvox miRNAs have identifiable targets with near perfect complementarity (Molnar et al, 2007;Li et al, 2014;Voshall et al, 2014) and recent evidence suggests that miRNA regulation of transcript expression in Chlamydomonas may operate, at least for certain targets, by translation repression (Ma et al, 2013;Yamasaki et al, 2013;Voshall et al, 2014).…”

“…C. reinhardtii has been shown to contain a complex set of endogenous sRNAs including miRNAs, phased siRNAs, as well as siRNAs originating from transposons and repeated DNA regions (Molnar et al, 2007;Zhao et al, 2007;Yamasaki et al, 2013;Voshall et al, 2014). Likewise, V. carteri has been demonstrated to possess miRNAs, many of them being preferentially enriched in either gonidia or somatic cells (Li et al, 2014). Interestingly, there appears to be little conservation of miRNA genes among algal species or with those encoded in the genomes of land plants or animals (Cerutti et al, 2011;Li et al, 2014;Voshall et al, 2014).…”

“…Likewise, V. carteri has been demonstrated to possess miRNAs, many of them being preferentially enriched in either gonidia or somatic cells (Li et al, 2014). Interestingly, there appears to be little conservation of miRNA genes among algal species or with those encoded in the genomes of land plants or animals (Cerutti et al, 2011;Li et al, 2014;Voshall et al, 2014).…”

“…Within the examined microalgae, candidate miRNAs have been experimentally identified in C. reinhardtii (Molnar et al, 2007;Zhao et al, 2007;Yamasaki et al, 2013;Voshall et al, 2014) and in V. carteri (Li et al, 2014), and potential endogenous targets have been predicted by computational approaches (Molnar et al, 2007;Zhao et al, 2007;Li et al, 2014;Voshall et al, 2014). However, target gene identification is a challenging problem (Thomas et al, 2010;Voshall et al, 2014) and the false-positive prediction rate for miRNA targets in microalgae is currently unknown.…”

miR-210 over-expression enhances mesenchymal stem cell survival in an oxidative stress environment through antioxidation and c-Met pathway activation

“…microRNAs (miRNAs, miRs), through a combination of translational blockade and/or mRNA degradation, have been widely reported to possess the potential to regulate pathological and physiological processes [7], including proliferation, differentiation, death, metabolism and oxidative stress. It is currently believed that thousands of classic (protein-encoding) genes are controlled via such mechanisms; furthermore, it has been shown that some miRNAs tend to be associated with some special functional regulatory mechanisms [8], such as miR-146a for inflammatory response [9] and miR-126 for angiogenesis modulation [10].…”