FE, a phloem-specific Myb-related protein, promotes flowering through transcriptional activation of FLOWERING LOCUS T and FLOWERING LOCUS T INTERACTING PROTEIN 1.

In many flowering plants, the transition to flowering is primarily affected by seasonal changes in day length (photoperiod). An inductive photoperiod promotes flowering via synthesis of a floral stimulus, called florigen. In Arabidopsis thaliana, the FLOWERING LOCUS T (FT) protein is an essential component of florigen, which is synthesized in leaf phloem companion cells and is transported through phloem tissue to the shoot apical meristem where floral morphogenesis is initiated. However, the molecular mechanism involved in the long-distance transport of FT protein remains elusive. In this study, we characterized the classic Arabidopsis mutant fe, which is involved in the photoperiodic induction of flowering, and showed that FE encodes a phloem-specific Myb-related protein that was previously reported as ALTERED PHLOEM DEVELOPMENT. Phenotypic analyses of the fe mutant showed that FT expression is reduced in leaf phloem companion cells. In addition, the transport of FT protein from leaves to the shoot apex is impaired in the fe mutant. Expression analyses further demonstrated that FE is also required for transcriptional activation of FLOWERING LOCUS T INTERACTING PROTEIN 1 (FTIP1), an essential regulator for selective trafficking of the FT protein from companion cells to sieve elements. These findings indicate that FE plays a dual role in the photoperiodic induction of flowering: as a transcriptional activator of FT on the one hand, and its transport machinery component, FTIP1, on the other hand. Thus, FE is likely to play a role in regulating FT by coordinating FT synthesis and FT transport in phloem companion cells.

MicroRNA-30a suppresses non-small-cell lung cancer by targeting Myb-related protein B.

Non-small-cell lung cancer (NSCLC) is one of the leading causes of cancer mortality worldwide. A growing body of evidence indicates that microRNA (miR) have important and diverse roles in the proliferation, apoptosis and metastasis of human cancer cells. In the present study, the molecular regulation mechanism of miR-30a and its potential target, Myb-related protein B (MYBL2) was investigated in NSCLC. Reverse transcription-quantitative polymerase chain reaction results showed that miR-30a was significantly downregulated in NSCLC tissues compared with adjacent normal tissues (P<0.05). MYBL2 has a putative miR-30a target site in its 3'untranslated region according to previous data, prediction databases and TargetScan software. In the present study, a negative correlation was demonstrated between miR-30a and MYBL2 expression in NSCLC. Direct interaction between miR-30a and MYBL2 was also confirmed via a dual-luciferase reporter assay. miR-30a overexpression inhibited the growth of A549 and H460 cells via MTT and bromodeoxyuridine incorporation assays, whereas miR-30a downregulation promoted cell proliferation. In addition, miR-30a overexpression not only increased cell apoptosis and induced cell cycle arrest in A549 and H460 cell lines, but also attenuated tumor growth, and mRNA and protein expression levels of MYBL2. The present findings suggest that miR-30a may suppress NSCLC by targeting MYBL2.

De novo transcriptome analysis of Liriodendron chinense petals and leaves by Illumina sequencing.

Liriodendron chinense (Hemsl.) Sarg is an endangered species and occupies a pivotal position in phylogenetic studies of flowering plants, while its genomic resources are limited. In this study, we performed transcriptome sequencing for L. chinense petals and leaves using the Illumina paired-end sequencing technique. Approximately 17.02-Gb clean reads were obtained, and de novo assembly generated 87,841 unigenes, with an average length of 778 bp. Of these, there were 65,535 (74.61%) unigenes with significant similarity to publically available plant protein sequences. There were 3386 genes identified as significant differentially expressed between petals and leaves, among them 2969 (87.68%) were up-regulated and 417 (12.31%) down-regulated in petals. Metabolic pathway analysis revealed that 25 unigenes were predicted to be responsible for the biosynthesis of carotenoids, with 7 genes differentially expressed between these two tissues. This report is the first to identify genes associated with carotenoid biosynthesis in Liriodendron and represents a valuable resource for future genomic studies on the endangered species L. chinense.