Phosphatidylethanolamine-binding Proteins Research Articles

PHOSPHATIDYLETHANOLAMINE-BINDING PROTEINS: the conductors of dual reproduction in plants with vegetative storage organs.

Geophytes, the plants that form vegetative storage organs, are characterized by a dual reproduction system, in which vegetative and sexual propagation are tightly regulated to ensure fitness in harsh climatic conditions. Recent findings highlight the role of the PEBP (PHOSPHATIDYLETHANOLAMINE-BINDING PROTEIN) gene family in geophytes as major players in the molecular cascades underlying both types of reproduction. In this review, we briefly explain the life cycle and reproduction strategies of different geophytes and what is known about the physiological aspects related to these processes. Subsequently, an in-depth overview is provided of the molecular and genetic pathways driving these processes. In the evolution of plants, the PEBP gene family has expanded, followed by neo- and subfunctionalization. Careful characterization revealed that differential expression and differential protein complex formation provide the members of this gene family with unique functions, enabling them to mediate the crosstalk between the two reproductive events in geophytes in response to environmental and endogenous cues. Taking all these studies into account, we propose to regard the PEBPs as conductors of geophyte reproductive development.

Molecular regulation of plant developmental transitions and plant architecture via PEPB family proteins: an update on mechanism of action.

This year marks the 100th anniversary of the experiments by Garner and Allard that showed that plants measure the duration of the night and day (the photoperiod) to time flowering. This discovery led to the identification of Flowering Locus T (FT) in Arabidopsis and Heading Date 3a (Hd3a) in rice as a mobile signal that promotes flowering in tissues distal to the site of cue perception. FT/Hd3a belong to the family of phosphatidylethanolamine-binding proteins (PEBPs). Collectively, these proteins control plant developmental transitions and plant architecture. Several excellent recent reviews have focused on the roles of PEBPs in diverse plant species; here we will primarily highlight recent advances that enhance our understanding of the mechanism of action of PEBPs and discuss critical open questions.

Sequence and functional analysis of a TERMINAL FLOWER 1 homolog from Brassica juncea: a putative biotechnological tool for flowering time adjustment

ABSTRACTFlowering time is an important agricultural trait of the oil crop Brassica juncea (B. juncea), as accelerated flowering enables avoidance of terminal drought leading to increased yields. One gene known to control flowering time is TERMINAL FLOWER 1 (TFL1), which belongs to a family of phosphatidylethanolamine binding proteins, which can either repress or promote flowering time. Here, a TFL1 homolog, named BjTFL1, has been isolated from B. juncea, which shared 95% amino acid identity with TFL1 from Arabidopsis thaliana. Sequence analysis predicts the BjTFL1 protein contains the ligand-binding site, conserved motifs and other amino acid residues that are critical for TFL1 function. Confirming this as a functional TFL1 orthologue, overexpression of BjTFL1 under the control of the constitutive 35S promoter in Arabidopsis delayed flowering time. As a proof-of-concept to investigate its utility to shorten flowering time, an RNAi construct containing a partial sequence of BjTFL1 was transformed into Arabidopsis. Transcript analysis demonstrated the downregulation of endogenous AtTFL1. Moreover, the RNAi BjTFL1 transgenic lines were early flowering and had fewer rosette and cauline leaves compared to wild-type. Therefore, this BjTFL1 RNAi transgene could be used as a biotechnological tool to reduce flowering time in Brassica juncea in a bid to improve agricultural performance.

Molecular and transcriptional characterization of phosphatidyl ethanolamine-binding proteins in wild peanuts Arachis duranensis and Arachis ipaensis

BackgroundPhosphatidyl ethanolamine-binding proteins (PEBPs) are involved in the regulation of plant architecture and flowering time. The functions of PEBP genes have been studied in many plant species. However, little is known about the characteristics and expression profiles of PEBP genes in wild peanut species, Arachis duranensis and Arachis ipaensis, the diploid ancestors of cultivated peanuts.ResultsIn this study, genome-wide identification methods were used to identify and characterize a total of 32 peanut PEBP genes, 16 from each of the two wild peanut species, A. duranensis and A. ipaensis. These PEBP genes were classified into 3 groups (TERMINAL FLOWER1-like, FLOWERING LOCUS T-like, and MOTHER OF FT AND TFL1-like) based on their phylogenetic relationships. The gene structures, motifs, and chromosomal locations for each of these PEBPs were analyzed. In addition, 4 interchromosomal duplications and 1 tandem duplication were identified in A. duranensis, and 2 interchromosomal paralogs and 1 tandem paralog were identified in A. ipaensis. Ninety-five different cis-acting elements were identified in the PEBP gene promoter regions and most genes had different numbers and types of cis-elements. As a result, the transcription patterns of these PEBP genes varied in different tissues and under long day and short day conditions during different growth phases, indicating the functional diversities of PEBPs in different tissues and their potential functions in plant photoperiod dependent developmental pathways. Moreover, our analysis revealed that AraduF950M/AraduWY2NX in A. duranensis, and Araip344D4/Araip4V81G in A. ipaensis are good candidates for regulating plant architecture, and that Aradu80YRY, AraduYY72S, and AraduEHZ9Y in A. duranensis and AraipVEP8T in A. ipaensis may be key factors regulating flowering time.ConclusionSixteen PEBP genes were identified and characterized from each of the two diploid wild peanut genomes, A. duranensis and A. ipaensis. Genetic characterization and spatio-temporal expression analysis support their importance in plant growth and development. These findings further our understanding of PEBP gene functions in plant species.

Identification and Characterization of the PEBP Family Genes in Moso Bamboo (Phyllostachys heterocycla)

Moso bamboo is one of the economically most important plants in China. Moso bamboo is a monocarpic perennial that exhibits poor and slow germination. Thus, the flowering often causes destruction of moso bamboo forestry. However, how control of flowering and seed germination are regulated in moso bamboo is largely unclear. In this study, we identified 5 members (PhFT1-5) of the phosphatidyl ethanolamine-binding proteins (PEBP) family from moso bamboo genome that regulate flowering, flower architecture and germination, and characterized the function of these PEBP family genes further in Arabidopsis. Phylogenetic analysis revealed that 3 (PhFT1, PhFT2 and PhFT3), 1 (PhFT4) and 1 (PhFT5) members belong to the TFL1-like clade, FT-like clade, and MFT-like clade, respectively. These PEBP family genes possess all structure necessary for PEBP gene function. The ectopic overexpression of PhFT4 and PhFT5 promotes flowering time in Arabidopsis, and that of PhFT1, PhFT2 and PhFT3 suppresses it. In addition, the overexpression of PhFT5 promotes seed germination rate. Interestingly, the overexpression of PhFT1 suppressed seed germination rate in Arabidopsis. The expression of PhFT1 and PhFT5 is significantly higher in seed than in tissues including leaf and shoot apical meristem, implying their function in seed germination. Taken together, our results suggested that the PEBP family genes play important roles as regulators of flowering and seed germination in moso bamboo and thereby are necessary for the sustainability of moso bamboo forest.

Differences in gene expression in whitefly associated with CYSDV-infected and virus-free melon, and comparison with expression in whiteflies fed on ToCV- and TYLCV-infected tomato

BackgroundCucurbit yellow stunting disorder virus (CYSDV; genus Crinivirus, Closteroviridae) is transmitted in a semipersistent manner by the whitefly, Bemisia tabaci, and is efficiently transmitted by the widely prevalent B. tabaci cryptic species, MEAM1. In this study, we compared transcriptome profiles of B. tabaci MEAM1, after 24 h, 72 h and 7 days of acquisition feeding on melon plants infected with CYSDV (CYSDV-whiteflies) with those fed on virus-free melon, using RNA-Seq technology. We also compared transcriptome profiles with whiteflies fed on tomato plants separately infected with Tomato chlorosis virus (ToCV), a crinivirus closely related to CYSDV, and Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, which has a distinctly different mode of transmission and their respective virus-free controls, to find common gene expression changes among viruliferous whiteflies feeding on different host plants infected with distinct (TYLCV) and related (CYSDV and ToCV) viruses.ResultsA total of 275 differentially expressed genes (DEGs) were identified in CYSDV-whiteflies, with 3 DEGs at 24 h, 221 DEGs at 72 h, and 51 DEGs at 7 days of virus acquisition. Changes in genes encoding orphan genes (54 genes), phosphatidylethanolamine-binding proteins (PEBP) (20 genes), and AAA-ATPase domain containing proteins (10 genes) were associated with the 72 h time point. Several more orphan genes (20 genes) were differentially expressed at 7 days. A total of 59 common DEGs were found between CYSDV-whiteflies and ToCV-whiteflies, which included 20 orphan genes and 6 lysosomal genes. A comparison of DEGs across the three different virus-host systems revealed 14 common DEGs, among which, eight showed similar and significant up-regulation in CYSDV-whiteflies at 72 h and TYLCV-whiteflies at 24 h, while down-regulation of the same genes was observed in ToCV-whiteflies at 72 h.ConclusionsDynamic gene expression changes occurred in CYSDV-whiteflies after 72 h feeding, with decreased gene expression changes associated with 7 days of CYSDV acquisition. Similarities in gene expression changes among CYSDV-whiteflies, ToCV-whiteflies and TYLCV-whiteflies suggest the possible involvement of common genes or pathways for virus acquisition and transmission by whiteflies, even for viruses with distinctly different modes of transmission.

Functional analysis and characterization of antimicrobial phosphatidylethanolamine-binding protein BmPEBP in the silkworm Bombyx mori

Phosphatidylethanolamine-binding proteins (PEBPs) are a class of highly conserved, biologically diverse proteins, which are widely distributed in plants, insects, and mammals. In this study, a Bombyx mori PEBP (BmPEBP) gene was reported, which encodes a protein composed of 209 amino acid residues. BmPEBP includes a predicted signal peptide, indicating that it is an extracellular protein, which differs from the cytoplasmic PEBPs of plants and mammals. Recombinant soluble BmPEBP was successfully synthesized using a prokaryotic expression system and was then purified effectively by Ni2+-NTA affinity chromatography and gel filtration. Far-ultraviolet circular dichroism spectra indicated that BmPEBP had a well-defined β-sheet structure, with the β-sheet content accounting for about 41% of the protein. BmPEBP had a relatively stable structure at temperatures ranging from 15 °C to 57.5 °C. The Tm, ΔH, and ΔS of BmPEBP were 62.27 °C ± 0.14 °C, 570.10 ± 0.17 kJ/mol, and 1.70 ± 0.03 KJ/(mol·K), respectively. Homology modeling analysis suggested that the active sites of BmPEBP were conserved, comprising Pro96, His111, and His143. Quantitative real-time PCR showed that BmPEBP was highly expressed in the silk gland and had very low expression in other tissues. However, BmPEBP expression was significantly upregulated in the larval fat body after infection with two kinds of fungi, Beauveria bassiana and Candida albicans. Moreover, in vitro fungal inhibition tests showed that BmPEBP could significantly inhibit the sporular growth of Saccharomyces cerevisiae, C. albicans, B. bassiana, and Aspergillus fumigatus. To our knowledge, this is the first report to reveal the antifungal role of a PEBP in insects.

Isolation and functional analysis of FLOWERING LOCUS T orthologous gene from Vanda hybrid

Vanda is an important ornamental tropical orchid in Thailand and shows great potential in international markets. Since there has been limited research on flowering processes and regulations, flower production programs cannot be properly managed. To understand the genetic mechanisms in the Vanda flowering process, the ortholog of the FLOWERING LOCUS T (FT) gene (VaFT) was isolated and characterized by using Vanda ‘Ratchaburi-Fusch Katsura’. An open reading frame of 531 bp, translating a protein of 176 amino acids (AAs), was obtained from VaFT. The AA sequence alignment of VaFT indicated that it contains a conserved domain, distinctive to the phosphatidylethanolamine-binding proteins (PEBPs) superfamily, and shares high homology with other orchid FT proteins: 93% of PaFT from Phalaenopsis aphrodite, 91% of CgFT from Cymbidium goeringii and 89% of OnFT from Oncidium Gower Ramsey. Ectopic expression of VaFT in transgenic Arabidopsis resulted in activation of floral meristem identity gene APETALA1 (AP1) and early flowering with fewer rosette leaves than non-transgenic Arabidopsis. Our data suggests that VaFT is apparently a PEBPs gene in orchids that conducts the transition of flowering.

Isolation and functional characterization of a novel FLOWERING LOCUS T homolog (NtFT5) in Nicotiana tabacum

The phosphatidyl ethanolamine-binding proteins (PEBPs) function primarily in regulating flowering in plants. Here, we report a genome-wide identification of PEBPs and functional characterization of a novel FLOWERING LOCUS T homolog (NtFT5) in tobacco, Nicotiana tabacum. Seven new PEBPs were identified by a genome-wide analysis from N. tabacum. Expression profile showed that NtFT5 was mainly expressed in flowers. Overexpression of NtFT5 conferred an early flowering phenotype. By optimizing rooting medium, heritable short life-cycle tobacco lines were obtained by overexpression of NtFT5. Several orthologs of flowering genes downstream of FT gene were up-regulated in the NtFT5-overexpression transgenic plant lines. The NtFT5-overexpressing tobaccos formed fewer flowers and seeds per capsule compared with wild type. The seed-to-seed life cycle of NtFT5 overexpressing tobacco lines was about 2.5 months. Gene identification was effectively undertaken in the short life-cycle tobacco line by a second transformation via a gusA reporter gene and transient expression of Ros1 via PVX (Potato Virus X)system. Our findings indicate that NtFT5 is a novel FT homolog that has potential to induce flowering, which will improve our understanding of the mechanism underlying flowering control in N. tabacum. In addition, the results show that the generated heritable short life-cycle transgenic tobacco line is an effective and stable host system to accelerate gene function study, which promises to provide a better tobacco research model for plants.

The FT/FD-dependent initiation of flowering under long-day conditions in the day-neutral species Nicotianatabacum originates from the facultative short-day ancestor Nicotianatomentosiformis.

Photoperiod is an important external stimulus governing the precise timing of the floral transition in plants. Members of the FLOWERING LOCUS T (FT)-like clade of phosphatidylethanolamine-binding proteins induce this developmental process in numerous species by forming regulatory protein complexes with FD-like bZIP transcription factors. We identified several thus far unknown FT-like and FD-like genes in the genus Nicotiana and found that, even in the day-neutral species Nicotianatabacum, floral initiation requires the photoperiod-dependent expression of several FT-like genes. Furthermore, floral promotion under long-day (LD) and short-day (SD) conditions is mediated by an FT-like protein (NtFT5) that originates from the genome of the paternal, facultative SD ancestor Nicotianatomentosiformis. In contrast, its ortholog of the maternal LD ancestor Nicotianasylvestris is not present in the genome of N.tabacum cv. SR1. Expression profiling in N.tabacum and its ancestors confirmed the relevance of these FT and FD orthologs in the context of polyploidization. We also found that floral inhibition by tobacco FT-like proteins is not restricted to SD conditions, highlighting the coincident expression of tobacco FT-like genes encoding floral activators and floral inhibitors. Multicolor bimolecular fluorescence complementation analysis revealed the preferential formation of FT/FD complexes that promote rather than inhibit flowering, which in concert with the regulation of NtFT and NtFD expression could explain how floral promotion overcomes floral repression during the floral transition in tobacco.

The draft genome of whitefly Bemisia tabaci MEAM1, a global crop pest, provides novel insights into virus transmission, host adaptation, and insecticide resistance.

BackgroundThe whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is among the 100 worst invasive species in the world. As one of the most important crop pests and virus vectors, B. tabaci causes substantial crop losses and poses a serious threat to global food security.ResultsWe report the 615-Mb high-quality genome sequence of B. tabaci Middle East-Asia Minor 1 (MEAM1), the first genome sequence in the Aleyrodidae family, which contains 15,664 protein-coding genes. The B. tabaci genome is highly divergent from other sequenced hemipteran genomes, sharing no detectable synteny. A number of known detoxification gene families, including cytochrome P450s and UDP-glucuronosyltransferases, are significantly expanded in B. tabaci. Other expanded gene families, including cathepsins, large clusters of tandemly duplicated B. tabaci-specific genes, and phosphatidylethanolamine-binding proteins (PEBPs), were found to be associated with virus acquisition and transmission and/or insecticide resistance, likely contributing to the global invasiveness and efficient virus transmission capacity of B. tabaci. The presence of 142 horizontally transferred genes from bacteria or fungi in the B. tabaci genome, including genes encoding hopanoid/sterol synthesis and xenobiotic detoxification enzymes that are not present in other insects, offers novel insights into the unique biological adaptations of this insect such as polyphagy and insecticide resistance. Interestingly, two adjacent bacterial pantothenate biosynthesis genes, panB and panC, have been co-transferred into B. tabaci and fused into a single gene that has acquired introns during its evolution.ConclusionsThe B. tabaci genome contains numerous genetic novelties, including expansions in gene families associated with insecticide resistance, detoxification and virus transmission, as well as numerous horizontally transferred genes from bacteria and fungi. We believe these novelties likely have shaped B. tabaci as a highly invasive polyphagous crop pest and efficient vector of plant viruses. The genome serves as a reference for resolving the B. tabaci cryptic species complex, understanding fundamental biological novelties, and providing valuable genetic information to assist the development of novel strategies for controlling whiteflies and the viruses they transmit.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-016-0321-y) contains supplementary material, which is available to authorized users.

Characterization of two PEBP genes, SrFT and SrMFT, in thermogenic skunk cabbage (Symplocarpus renifolius).

Floral thermogenesis has been found in dozens of primitive seed plants and the reproductive organs in these plants produce heat during anthesis. Thus, characterization of the molecular mechanisms underlying flowering is required to fully understand the role of thermogenesis, but this aspect of thermogenic plant development is largely unknown. In this study, extensive database searches and cloning experiments suggest that thermogenic skunk cabbage (Symplocarpus renifolius), which is a member of the family Araceae, possesses two genes encoding phosphatidyl ethanolamine-binding proteins (PEBP), FLOWERING LOCUS T (SrFT) and MOTHER OF FT AND TFL1 (SrMFT). Functional analyses of SrFT and SrMFT in Arabidopsis indicate that SrFT promotes flowering, whereas SrMFT does not. In S. renifolius, the stage- and tissue-specific expression of SrFT was more evident than that of SrMFT. SrFT was highly expressed in flowers and leaves and was mainly localized in fibrovascular tissues. In addition, microarray analysis revealed that, within floral tissues, SrFT was co-regulated with the genes associated with cellular respiration and mitochondrial function, including ALTERNATIVE OXIDASE gene proposed to play a major role in floral thermogenesis. Taken together, these data suggest that, among the PEBP genes, SrFT plays a role in flowering and floral development in the thermogenic skunk cabbage.

Heterologous Production of Fungal Maleidrides Reveals the Cryptic Cyclization Involved in their Biosynthesis.

Fungal maleidrides are an important family of bioactive secondary metabolites that consist of 7, 8, or 9‐membered carbocycles with one or two fused maleic anhydride moieties. The biosynthesis of byssochlamic acid (a nonadride) and agnestadride A (a heptadride) was investigated through gene disruption and heterologous expression experiments. The results reveal that the precursors for cyclization are formed by an iterative highly reducing fungal polyketide synthase supported by a hydrolase, together with two citrate‐processing enzymes. The enigmatic ring formation is catalyzed by two proteins with homology to ketosteroid isomerases, and assisted by two proteins with homology to phosphatidylethanolamine‐binding proteins.

Synthesis and evaluation of locostatin-based chemical probes towards PEBP-proteins

Phosphatidyl ethanolamine-binding proteins (PEBPs) are implicated in various critical physiological processes in all eukaryotes. Among them is Flowering Locus T (FT), the protein recently discovered as the vital flowering hormone in plants. Small molecule inhibitors and activators of FT could provide control over plant flowering and are therefore an interesting target for industrial agriculture. No small molecule inhibitors or activators are known for FT, but for a structurally similar PEBP, RKIP, an inhibitor called locostatin has been reported to covalently bind in the RKIP ligand binding pocket. Herein, we report the synthesis of novel locostatin-based chemical PEBP probes and evaluate their ability and selectivity towards the binding of FT and RKIP.

Phosphatidylethanolamine binding protein 4 (PEBP4) is a secreted protein and has multiple functions

Phosphatidylethanolamine binding proteins (PEBP) represent a superfamily of proteins that are conserved from bacteria to humans. In mammals, four members have been identified, PEBP1–4. To determine the functional differences among PEBP1–4 and the underlying mechanism for their actions, we performed a sequence alignment and found that PEBP4 contains a signal peptide and potential glycosylation sites, whereas PEBP1–3 are intracellular proteins. To test if PEBP4 is secreted, we made constructs with Myc epitope at the amino (N) terminus or carboxyl (C) terminus to mask the signal sequence or keep it free, respectively. Our data revealed that both mouse and human PEBP4 were secreted when the epitope was tagged at their C-terminus. To our surprise, secretion was dependent upon the C-terminal conserved domain in addition to the N-terminal signal sequence. When the epitope was placed to the N-terminus, the recombinant protein failed to secrete and instead, was retained in the cytoplasm. Mass spectrometry detected asparagine (N)-glycosylation on the secreted PEBP4. Although overexpression of N-terminal tagged PEBP4 resulted in an inhibition of ERK activation by EGF, that with a C-terminal epitope tag did not have such an effect. Likewise, transfection of PEBP4 shRNA did not appear to affect ERK activation, suggesting that PEBP4 does not participate in the regulation of this pathway. In contrast, PEBP4 siRNA suppressed phosphorylation of Act at S473. Therefore, our results suggest that PEBP4 is a multifunctional protein and can be secreted. It will be important to investigate the mechanism by which PEBP4 is secreted and regulates cellular events.

Functional evolution of phosphatidylethanolamine binding proteins in soybean and Arabidopsis.

Gene duplication provides resources for novel gene functions. Identification of the amino acids responsible for functional conservation and divergence of duplicated genes will strengthen our understanding of their evolutionary course. Here, we conducted a systemic functional investigation of phosphatidylethanolamine binding proteins (PEBPs) in soybean (Glycine max) and Arabidopsis thaliana. Our results demonstrated that after the ancestral duplication, the lineage of the common ancestor of the FLOWERING LOCUS T (FT) and TERMINAL FLOWER1 (TFL1) subfamilies functionally diverged from the MOTHER OF FT AND TFL1 (MFT) subfamily to activate flowering and repress flowering, respectively. They also underwent further specialization after subsequent duplications. Although the functional divergence increased with duplication age, we observed rapid functional divergence for a few pairs of young duplicates in soybean. Association analysis between amino acids and functional variations identified critical amino acid residues that led to functional differences in PEBP members. Using transgenic analysis, we validated a subset of these differences. We report clear experimental evidence for the functional evolution of the PEBPs in the MFT, FT, and TFL1 subfamilies, which predate the origin of angiosperms. Our results highlight the role of amino acid divergence in driving evolutionary novelty after duplication.

Identification of PEBP Gene Family in Gossypium arboreum and Gossypium raimondii and Expression Analysis of the Gene Family in Gossypium hirsutum

The phosphatidylethanolamine-binding proteins(PEBP) widely exist in eukaryotes. In angiosperms, PEBP family genes play important role in promoting or inhibiting flowering, as well as plant architecture control. Eight PEBP genes were identified from diploid cotton Gossypium arboreum(A2) and Gossypium raimondii(D5) genome database, respectively. All the PEBP genes of cotton contained four exons and three introns, and their encoded proteins contained a conserved PEBP motif and critical amino acid sites of PEBP family, which indicated there were at least eight PEBP genes in diploid cotton. Phylogenetic analysis showed that eight cotton PEBP genes comprised three subfamilies: FLOWERING LOCUS T(FT)-like containing one gene, TERMINAL FLOWER 1(TFL1)-like containing five genes including three TFL1 and two BFT genes, and MOTHER OF FT AND TFL1(MFT)-like containing two genes. The expression patterns of eight Gossypium hirsutum PEBP family genes in root, stem, leaf, shoot apical meristem, flower, ovule and 25 days post-anthesis(DPA) fiber were determined with quantitative Real-time reverse transcription PCR(q RT-PCR). The results showed that FT1 transcript was preferentially expressed in leaf and secondly in fiber, ovule and flower. MFT1 expressed in all the tissues, with the highest expression level in fiber, then in flower and leaf, while MFT2 transcript was preferentially expressed in leaf. TFL1 a, TFL1 b, and TFL1 c expressed mainly in root, and TFL1 c also expressed in leaf, flower and ovule. Expression of BFT1 and BFT2 were present mainly in leaf, and that of BFT1 in the other six tissues except for shoot apical meristem(SAM) were higher than that of BFT2. Expression analysis revealed that eight PEBP genes in cotton have different expression patterns, showing their different functional roles in regulation of cotton development.

Identification and Characterization of the FT/TFL1 Gene Family in the Biofuel Plant Jatropha curcas

The transition from vegetative to reproductive growth is one of the most important developmental steps made by flowering plants. At the molecular level, the genes in the FLOWERING LOCUS T (FT)/TERMINAL FLOWER 1 (TFL1) family, which encode proteins with high similarity to phosphatidyl ethanolamine-binding proteins, function as flowering promoters or repressors. Here, we isolated six members of the FT/TFL1 family from Jatropha curcas, a plant with considerable potential for various uses including biofuels. All members of this gene family display a common exon-intron organization. Sequence comparisons and phylogenetic analysis with homologous genes from other plant species group Jatropha FT/TFL1 genes into three major subfamilies: one into the FT-like, three into the TFL1-like, and two into the MOTHER OF FT AND TFL1 (MFT)-like subfamilies. Expression analysis indicates differences in the expression patterns of these six genes at the temporal and spatial levels. JcFT, the Jatropha FT homolog, is primarily expressed in the reproductive organs. JcTFL1a and JcTFL1c, two genes in the TFL1-like subfamily, are mainly expressed in the roots of juvenile plants, whereas JcTFL1b transcripts are abundantly accumulated in the fruits. In addition, two JcMFT genes are primarily expressed in the fruits. The differential expression of the FT/TFL1 gene family in Jatropha suggests that this gene family plays multifaceted roles in plant growth and development.

Expression of Raf Kinase Inhibitor Protein (RKIP) is a predictor of uveal melanoma metastasis.

Melanoma arising from melanocytes within the choroid is the most frequent primary intraocular neoplasm in adults. It is biologically distinct from cutaneous melanoma by a very strong propensity to metastasize the liver. Raf kinase inhibitor protein is a member of an evolutionarily conserved group of proteins called phosphatidylethanolamine-binding proteins. It is an interacting partner of Raf-1 and a negative regulator of the mitogen-activated protein kinase cascade initiated by Raf-1. Raf kinase inhibitor protein expression is low in many human cancers and represents an indicator of poor prognosis and/or induction of metastasis. In the present study, we examined the immunohistochemical expression levels of Raf kinase inhibitor protein and phosphorylated Raf kinase inhibitor protein in primary uveal melanoma with and without metastasis, and evaluated their association with other high risk characteristics for metastasis in order to assess whether Raf kinase inhibitor protein and phosphorylated Raf kinase inhibitor protein can be used to predict metastasis. A significant low expression of Raf kinase inhibitor protein was seen in patients with metastasis but not in patients without metastasis. The latter more frequently had a high expression of Raf kinase inhibitor protein. No significant difference was seen in phosphorylated Raf kinase inhibitor protein expression between patients with and without metastasis. Raf kinase inhibitor protein expression is a suitable and easily determinable marker in the primary tumour that could predict the risk of uveal melanoma to metastasize, and hence guide strategies for monitoring and therapy.

Proteinases in excretory-secretory products of Toxocara canis second-stage larvae: zymography and modeling insights.

Components released in excretory-secretory products of Toxocara canis larvae (TES) include phosphatidylethanolamine-binding proteins (TES26), mucins (TES120, MUC2-5), and C-type lectins (TES32, TES70) and their biochemical, immunological, and diagnostic properties have been extensively studied albeit proteinase activities towards physiological substrates are almost unknown. Proteolytic activities in TES samples were first analyzed by gel electrophoresis with gelatin as substrate. Major activities of ~400, 120, and 32 kDa in TES were relatively similar over a broad pH range (5.5–9.0) and all these were of the serine-type as leupeptin abolished gelatinolysis. Further, the ~400 kDa component degraded all physiological substrates tested (laminin, fibronectin, albumin, and goat IgG) and the 120 kDa component degraded albumin and goat IgG while proteinases of lower MW (45, 32, and 26 kDa) only degraded laminin and fibronectin, preferentially at alkaline pH (9.0). By protein modeling approaches using the known sequences of TES components, only TES26 and MUC4 displayed folding patterns significantly related to reference serine proteinases. These data suggest that most of serine proteinase activities secreted in vitro by infective larvae of T. canis have intriguing nature but otherwise help the parasite to affect multiple components of somatic organs and bodily fluids within the infected host.