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MicroRNA-mediated regulation of flower development in grasses

100%

Smoczynska A. , Szweykowska-Kulinska Z.

Acta Biochimica Polonica

2016

tom 63

nr 4

687-692

Flower structure in grasses is very unique. There are no petals or sepals like in eudicots but instead flowers develop bract-like structures - palea and lemma. Reproductive organs are enclosed by round lodicule that not only protects reproductive organs but also plays an important role during flower opening. The first genetic model for floral organ development was proposed 25 years ago and it was based on the research on model eudicots. Since then, studies have been carried out to answer the question whether this model could be applicable in the case of monocots. Genes from all classes found in eudicots have been also identified in genomes of such monocots like rice, maize or barley. What's more, it seems that miRNA-mediated regulation of floral organ genes that was observed in the case of Arabidopsis thaliana also takes place in monocots. MiRNA172, miRNA159, miRNA171 and miRNA396 regulate expression of floral organ identity genes in barley, rice and maize, affecting various features of the flower structure, ranging from formation of lemma and palea to the development of reproductive organs. A model of floral development in grasses and its genetic regulation is not yet fully characterized. Further studies on both, the model eudicots and grasses, are needed to unravel this topic. This review provides general overview of genetic model of flower organ identity specification in monocots and it's miRNA-mediated regulation.

STAT activation and differential complex formation dictate selectivity of interferon responses

80%

Wesoly J. , Szweykowska-Kulinska Z. , Bluyssen H. A. R.

Acta Biochimica Polonica

2007

tom 54

nr 1

27-38

Interferons (IFNs) induce gene expression by phosphorylating latent transcription factors belonging to the signal transducer and activator of transcription (STAT) family, mediated by janus kinases (Jaks). STAT dimers directly activate genes containing the IFNγ activation site (GAS) DNA element, with different STAT proteins displaying slightly different intrinsic DNA binding specificities. The combinatorial association of STATs with the additional DNA binding adaptor protein interferon regulatory factor (IRF)9 expands the range of enhancer elements that can be targeted by the JAK-STAT pathway to interferon-stimulated response element (ISRE) and IRF response element (IRE). Based on the amino-acid sequence similarity within the IRF family and functional overlap with the STAT family, in this paper we hypothesize that other IRF members could serve as adapter proteins for the STATs during IFN responses to redirect them to subsets of ISRE, GAS and/or IRE-containing IFN-stimulated genes (ISGs). In addition, the fact that STAT2 homodimers are not capable of binding consensus GAS sites leaves the possibility for a novel type of DNA-binding site bound by STAT2 homodimers and potentially other STAT complexes.

Developmental changes in barley microRNA expression profiles coupled with miRNA target analysis

61%

Pacak A. , Kruszka K. , Swida-Barteczka A. , Nuc P. , Karlowski W. , Jarmolowski A. , Szweykowska-Kulinska Z.

Acta Biochimica Polonica

2016

tom 63

nr 4

799-809

MicroRNAs are 19- to 24-nt-long single-stranded RNAs that are crucial regulators of gene expression which control plant development and response to environmental cues. We have analyzed microtranscriptomes of five barley developmental stages. Generally, during the barley development, miR168-3p and miR1432-5p levels increase while the 5'U-miR156-5p level decreases (with exception for the 2-week-old barley). We have identified two miR156-5p izomiRs (called 5'U-miR156-5p [20 nt] and 5'UU-miR156-5p [21 nt]), which were expressed differently during barley development. The 5' U-miR156-5p level decreased in 3-week-, 6-week-, and 68-day-old barley, when compared to the 1-week-old plants. Meanwhile, the 5' UU-miR156-5p level increased significantly in the 68-day-old barley plants. Moreover, only the 5' U-miR156 isomiR recognizes and guides unique transcription factor mRNAs from the Squamosa Promoter Binding Protein-Like (SPL) family. We identified many non-canonical microRNAs with changed expression levels during the barley development. Here, we present the profiles of microRNA expression characteristics for particular barley developmental stages. These analyses are accompanied by the experimental degradome analysis of miRNA targets.