Search

Cyclin-dependent kinase (CDK), the pivotal controller of cell cycle progression, is involved in stress resistance and plant growth. Moso bamboo (Phyllostachys edulis) with surprisingly rapid growth depends on continuous cell division, but the CDK gene family information is still lacking. Here, we performed the systematic identification and analysis of the CDK genes in moso bamboo. 40 PeCDK genes were identified and divided into eight subgroups via phylogeny. The same subgroup possessed extremely conserved sequences and similar gene structure. In addition, evolutionary analysis suggested that the PeCDK gene family may have experienced extensive duplication events primarily 6.85–13.71 million years ago (MYA), with segmental duplication dominating. Furthermore, the multiple promoter cis-elements determined in PeCDK genes indicated their potential functions. The expression patterns revealed that most PeCDK genes participated in responses to drought, salt, ABA and SA signals, cell wall synthesis, organ developmental processes and callus growth. The insights gained provide beneficial reference for clarifying the functions of PeCDKs as well as exploring the growth mechanism in bamboo. [ABSTRACT FROM AUTHOR]

Background: Eukaryotic genes contain introns that are removed by the spliceosomal machinery during mRNA maturation. Introns impose a huge energetic burden on a cell; therefore, they must play an essential role in maintaining genome stability and/or regulating gene expression. Many genes (> 50%) in Plasmodium parasites contain predicted introns, including introns in 5′ and 3′ untranslated regions (UTR). However, the roles of UTR introns in the gene expression of malaria parasites remain unknown. Methods: In this study, an episomal dual-luciferase assay was developed to evaluate gene expression driven by promoters with or without a 5′UTR intron from four Plasmodium yoelii genes. To investigate the effect of the 5′UTR intron on endogenous gene expression, the pytctp gene was tagged with 3xHA at the N-terminal of the coding region, and parasites with or without the 5′UTR intron were generated using the CRISPR/Cas9 system. Results: We showed that promoters with 5′UTR introns had higher activities in driving gene expression than those without 5′UTR introns. The results were confirmed in recombinant parasites expressing an HA-tagged gene (pytctp) driven by promoter with or without 5′UTR intron. The enhancement of gene expression was intron size dependent, but not the DNA sequence, e.g. the longer the intron, the higher levels of expression. Similar results were observed when a promoter from one strain of P. yoelii was introduced into different parasite strains. Finally, the 5′UTR introns were alternatively spliced in different parasite development stages, suggesting an active mechanism employed by the parasites to regulate gene expression in various developmental stages. Conclusions: Plasmodium 5′UTR introns enhance gene expression in a size-dependent manner; the presence of alternatively spliced mRNAs in different parasite developmental stages suggests that alternative slicing of 5′UTR introns is one of the key mechanisms in regulating parasite gene expression and differentiation. [ABSTRACT FROM AUTHOR]

Silicon (Si) has crucial effects on plant development and stress resistance. Silicon transporters regulate Si absorption, transport, and distribution in plants. In this study, we identified and characterized the Si transporter gene family of moso bamboo (Phyllostachys edulis) and cloned seven putative Si transporter genes. Moso bamboo Si transporters contain conserved functional domains that mediate the accumulation of considerable amounts of Si. The analysis of gene duplication patterns and divergence times suggested that the expansion of the moso bamboo Si transporter family was mainly due to segmental duplications. The expression of moso bamboo Si transporter genes, which varied among organs, was significantly modulated by Si treatments. The subcellular localization analysis showed that Si transporters are plasma membrane proteins. The Si content increased in transgenic Arabidopsis overexpressing PeLsi1-1 or PeLsi1-2 , which affected vegetative and reproductive growth. Our single-particle tracking analysis revealed the four diffusion modes of PeLsi1-1 on the plasma membrane. Moreover, the particle velocity, dwell time, and motion range of PeLsi1-1 decreased in response to Si treatments. The results of this study will further clarify the molecular mechanisms underlying Si absorption and accumulation in bamboo plants. • Moso bamboo has the molecular basis of high silicon accumulation. • The excessive accumulation of silicon affected the growth of transgenic Arabidopsis. • The distribution and dynamic changes of PeLsi1-1 were affected by silicon. • A hypothetical model for silicon transport in moso bamboo seedlings was established. [ABSTRACT FROM AUTHOR]

Abstract: The delivery of plasmid DNA to target cells using a simple, defined, non-viral system is an area of intense research in gene therapy. Here, we describe a novel DNA carrier protein termed TG, consisting of the DNA-binding domain of the yeast transcriptional activator GAL4 and human immunodeficiency virus type 1 Tat protein, which can transfer modified naked plasmid DNA into target cells to express foreign genes of interest. The TG protein was expressed in Escherichia coli (E. coli), refolded and purified on an immobilized Ni2+ affinity chromatography column. SDS–PAGE and Western blotting revealed that the fusion protein was highly expressed with a yield of approximately 275mg/L. We also constructed the pIRES-UAS-EGFP DNA vector, consisting of upstream activating sequences (UASs) for the specific binding of the DNA-binding protein and the enhanced green fluorescent protein (EGFP) gene. The TG protein could bind specifically to pIRES-UAS-EGFP, forming a complex which could efficiently transfect target cells and result in detectable EGFP protein expression. Thus, these results provide a basis for development of efficient non-viral DNA transfer vectors for further improvements of gene therapy strategies. [ABSTRACT FROM AUTHOR]