Long intergenic noncoding RNAs (lincRNAs) transcribed from intergenic regions of yeast and animal genomes play important roles in key biological processes. Yet, plant lincRNAs remain poorly characterized and how lincRNA biogenesis is regulated is unclear. Using a reproducibility-based bioinformatics strategy to analyze 200 Arabidopsis thaliana transcriptome data sets, we identified 13,230 intergenic transcripts of which 6480 can be classified as lincRNAs. Expression of 2708 lincRNAs was detected by RNA sequencing experiments. Transcriptome profiling by custom microarrays revealed that the majority of these lincRNAs are expressed at a level between those of mRNAs and precursors of miRNAs. A subset of lincRNA genes shows organ-specific expression, whereas others are responsive to biotic and/or abiotic stresses. Further analysis of transcriptome data in 11 mutants uncovered SERRATE, CAP BINDING PROTEIN20 (CBP20), and CBP80 as regulators of lincRNA expression and biogenesis. RT-PCR experiments confirmed these three proteins are also needed for splicing of a small group of introncontaining lincRNAs.
Summary
Since their discovery more than two decades ago, animal long noncoding RNAs (lncRNAs) have emerged as important regulators of many biological processes. Recently, a large number of lncRNAs have also been identified in higher plants, and here, we review their identification, classification and known regulatory functions in various developmental events and stress responses. Knowledge gained from a deeper understanding of this special group of noncoding RNAs may lead to biotechnological improvement of crops. Some possible examples in this direction are discussed.
Lantipeptides are ribosomally synthesized and posttranslationally
modified peptides containing lanthionine and/or labionin structures.
In this study, a novel class III lantipeptide termed catenulipeptin
was discovered from Catenulispora acidiphila DSM
44928, and its biosynthesis was reconstituted in vitro. The multifunctional enzyme AciKC catalyzes both dehydration and
cyclization of its peptide substrate AciA and installs two labionin
structures in catenulipeptin. AciKC shows promiscuity with respect
to cosubstrate and accepts all four NTPs. The C-terminal domain of
AciKC is responsible for the labionin formation in catenulipeptin.
The cyclase activity of AciKC requires the leader peptide of AciA
substrate but does not require ATP or Zn2+. Mutagenesis
studies suggest that the labionin cyclization may proceed in a C-to-N-terminal
direction. Catenulipeptin partially restores aerial hyphae growth
when applied to surfactin-treated Streptomyces coelicolor.
Adiposity is commonly associated with adipose tissue dysfunction and many overnutrition-related metabolic diseases including type 2 diabetes. Much attention has been paid to reducing adiposity as a way to improve adipose tissue function and systemic insulin sensitivity. PFKFB3/iPFK2 is a master regulator of adipocyte nutrient metabolism. Using PFKFB3 In an in vitro system, knockdown of PFKFB3/iPFK2 in 3T3-L1 adipocytes caused a decrease in the rate of glucose incorporation into lipid but an increase in the production of reactive oxygen species. Furthermore, knockdown of PFKFB3/iPFK2 in 3T3-L1 adipocytes inappropriately altered the expression of adipokines, decreased insulin signaling, increased the phosphorylation states of JNK and NFB p65, and enhanced the production of proinflammatory cytokines. Together, these data suggest that PFKFB3/iPFK2, although contributing to adiposity, protects against diet-induced insulin resistance and adipose tissue inflammatory response.
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