The identity of toxin producers remains only hypothesis unless there were identified by strain isolation and analytical confirmation of both the cyanotoxin production and the genetic identity of the monoculture. The purposes of this study were to identify a morphologic and phylogenetic classification in Aphanizomenon flos-aquae strains isolated from the Nakdong River and to investigate the potential ability of the strains to produce toxins such as saxitoxin and cylindrospermopsin using target genes. The 16S rRNA and sxtA, sxtI, cyrA, cyrJ genes were analyzed on two strains (DGUC001, DGUC003) isolated from the Nakdong River. Morphological features of the strains were observed a shape of aggregated trichomes in parallel fascicles which can reach up to macroscopic size and a hyaline terminal cell without aerotope. In addition, the 16S rRNA phylogenetic analyses showed that the strains were identified as the same species with high genetic similarity of 98.4% and grouped within a monospecific andsupported cluster I of Aphanizomenon flosaquae selected from GenBank of the NCBI. The cyrA and cyrJ genes encoding for the cylindrospermopsinbiosynthesis were not detected in the present study. The sxtA gene was in detected both the two strains, whereas the sxtI gene which had been suggested as a suitable molecular marker to detect saxitoxin-producing cyanobacteria was not found both the strains. Thus, the two strains isolated from Nakdong River were identified as the same species of Aphanizomenon flos-aquae Ralfs ex Bornet et Flahault 1888, the two strains were confirmed as potential non-producing strains of the saxitoxin and cylindrospermopsin.
Matrix Metalloproteinases (both MMP2 and -9) play a pivotal role of the embryos hatching and implantation. Therefore, the objective of this study was carried out to investigate the influence of MMP2 and MMP9 on embryo development potential and subsequent effect at molecular level. There was no significant difference of cleavage rate among the groups. The development competence of blastocyst was significantly higher (P<0.05) in MMP9 treatment (39.81±16.61) than that to the combined treatment of MMP2 and –9 (23.68±0.27), but there was no significant difference among the control vs. MMP2 vs. MMP9 (35.05±2.74 vs. 32.71±6.18 vs. 39.81±16.61, respectively). On the other hand, the hatching rate of blastocysts was significantly lower (P<0.05) in combined group of MMP2 and –9 (12.55±0.09) (Table1). The expression level of MMP2 and MMP9 was significantly lower (P<0.05) in the entire treatment groups than that in the control group. But the expression of MMP9 was significantly higher (P<0.05) when compared in the entire treatment groups. The relative expression embryonic developmental gene, IFNt expression level significantly lower (P < 0.05) in the MMP9 embryos. The placenta establishment genes, PLAC8 and SSLP1, expression were significantly higher (P < 0.05) in the MMP2 embryos compared to other groups. Transcription regulation gene, HNRNPA2B1, was higher (P < 0.05) in the combined group of MMP2+MMP9 than that in the other groups. In conclusion, our results suggest that MMPs to culture medium improves the blastocyst development rate and further impact on target gene expression analysis.
A viral histone H4 (=CpBV-H4) is encoded in a polydnavirus, Cotesia plutellae bracovirus, and symbiotically associated with an endoparasitoid wasp, C. plutellae. It has an extended N-terminal tail consisting of 38 amino acid residues, compared to the host H4 and this extended N-terminal tail has been postulated to play a crucial role in an epigenetic control of gene expression. The (SSH) suppression subtractive hybridization analysis was analyzed in transcriptome by short-read sequencing technology. The SSH analysis provided several target and nontarget genes of a viral histone H4. In this study, we analyzed the effect CpBV-H4 on the expression of two target genes serpins and histone lysine N-methyl transferase. Transient expression of CpBV-H4 by microinjecting recombinant expression vector to non parasitized larvae of Plutella xylostella showed that it was expressed up to 70 h. Under this transient expression condition, we analyzed the effect of CpBV-H4 on the expression of target genes by RT-PCR at different time points. Interestingly, the CpBV-H4 significantly inhibited the expression of target genes after 44 h, while the truncated CpBV-H4 deleting the N-terminal tail did not show the inhibitory activity.
The stable fly, Stomoxys calcitrans L., is an important pest of livestock. Stable flies are considered as mechanical vectors of veterinary disease. Pyrethroids and organophosphates have been widely used for stable fly control. To establish resistance monitoring molecular tool, we isolated the partial cDNA and genomic fragments of voltage-sensitive sodium channel and acetylcholinesterase genes encompassing the well known conserved sites for resistance-associated mutations. To examine the current status of stable fly resistance to pyrethroids and organophosphates mediated by the nerve insensitivity mechanism in Korean population of S. calcitrans, DNA-based genotyping in conjunction with residual contact vial (RCV) bioassay were conducted with 11 representative regional field populations. No resistance-associated mutations were detected in these S. calcitrans populations, suggesting that these populations are likely still susceptible to both pyrethroids and organophosphates. Establishment of RCV bioassay protocol and availalbility of target site sequence information will greatly facilitate resistance monitoring of S. calcitrans in the field.
Spatial- and temporal-specific expression patterns are primarily regulated at the transcriptional level by the promoter. Therefore, it is important to determine the binding motifs of transcription factors to understand the networks associated with embryogenesis. Here, we used a protein-binding microarray (PBM) to determine the binding motif of OsSMF1, which is a basic leucine zipper transcription factor that is involved in the regulation of rice seed maturation. OsSMF1 (previously called RISBZ1) is known to interact with GCN4 motifs (TGA(G/C)TCA) to regulate seed storage proteins (SSPs). In addition, OsSMF1 (also known as OsbZIP58) functions as a key regulator of starch synthesis in the rice seed. Quadruple 9-mer-based PBM (Q9-PBM) and electrophoretic mobility shift assay (EMSA) experiments revealed that OsSMF1 binds to the ACGT (CCACGT(C/G)), GCN4 (TGA(G/C)TCA), and GCN4-like (GGATGAC) motifs with Kd values of 0.3353 μM, 0.6458 μM, and 1.117 μM, respectively. We also identified 60 putative OsSMF1 target genes using a combination of data from expression microarrays and RiceArrayNet (RAN) analysis. Of these OsSMF1 target genes, 20, 22, and 17 genes contained ACGT, GCN4, and GCN4-like motifs within the 2-kb promoter region, respectively. In addition to known target genes, we also identified 35 potential OsSMF1 target genes that have not been previously described in immature seeds. We also confirmed that OsSMF1 directly regulates Os03g0168500 (thioredoxin-related protein), RPBF, NAC6, and two hypothetical proteins (Os12g0621600 and Os11g0582400) in vivo. This study suggests that OsSMF1 functions in a wide range of seed development processes with specific binding affinities for three DNA binding motifs
Early growth response 1 (Egr1) is a zinc-finger transcription factor to direct second-wave gene expression leading to cell growth, differentiation and/or apoptosis. While it is well-known that Egr1 controls transcription of an array of targets in various cell types, downstream target gene(s) whose transcription is regulated by Egr1 in the uterus has not been identified yet. Thus, we have tried to identify a list of potential target genes of Egr1 in the uterus by performing multi-step in silico promoter analyses. Analyses of mRNA microarray data provided a cohort of genes (102 genes) which were differentially expressed (DEGs) in the uterus between Egr1(+/+) and Egr1(–/–) mice. In mice, the frequency of putative EGR1 binding sites (EBS) in the promoter of DEGs is significantly higher than that of randomly selected non-DEGs, although it is not correlated with expression levels of DEGs. Furthermore, EBS are considerably enriched within –500 bp of DEG’s promoters. Comparative analyses for EBS of DEGs with the promoters of other species provided power to distinguish DEGs with higher probability as EGR1 direct target genes. Eleven EBS in the promoters of 9 genes among analyzed DEGs are conserved between various species including human. In conclusion, this study provides evidence that analyses of mRNA expression profiles followed by two-step in silico analyses could provide a list of putative Egr1 direct target genes in the uterus where any known direct target genes are yet reported for further functional studies.
Early growth response 1 (Egr1) is an immediate early response gene which is induced by various external stimuli and acts as transcription factor to direct second-wave gene expression leading to cell growth, differentiation and/or apoptosis. It is well known that Egr1 regulates transcription of a cluster of genes in cancers and luteinizing hormone (LH) beta subunit in the pituitary. In addition to function of Egr1 in cancers and pituitary, we recently showed that Egr1 acts as a local master regulator to mediate estrogenic actions in the uterus. However, regulatory mechanism by which Egr1 directs transcription of its downstream target genes in the uterus remains to be yet explored. Thus, we have tried to identify direct target genes of Egr1 in the uterus by analyzing mRNA microarray data sets followed by in silico promoter analyses with chromatin immunoprecipitation (CHIP). mRNA expression profiles of Egr1(-/-) uteri and Egr1(-/-) ovaries were compared to those of wildtype mice to provide a potential list of direct target genes of Egr1 in the uterus. Whereas Egr1 is rapidly and transiently induced in the ovary and the uterus by external stimuli, LH and estrogen, respectively with a similar manner, a list of differentially expressed genes between Egr1(+/+) and Egr1(-/-) mice were barely overlapped between these two datasets. This result suggests that the transcriptional network of Egr1 in the uterus is quite different from that in the ovary. The list of differentially expressed genes in Egr1(-/-) uterus was enriched by RT-PCR. In silico analyses with MatInspector provided evidence that Egr1 binding sites are relatively enriched in -500 bp promoter regions of genes in the list. CHIP assays for Egr1 antibody with uterine tissues 2 h after estrogen treatment reinforced the possibility that genes identified in this study such as Gadd45g and Lbh could be directly regulated by Egr1 in uterine context. Collectively, we show that bioinformatic analyses of expression profiles with in silico analyses could be a useful tool to enrich potential candidates of direct target genes of transcription factors.
Lhx8 is a member of the LIM-homeobox transcription factor family expressed in the mouse ovary. We discovered that Lhx8 knockout females lose oocytes within 7 days after birth. Lhx8–/–ovaries fail to maintain the primordial follicles and growing follicles. Lhx8–/–ovaries misexpress numerous oocyte-specific genes such as H1foo and Nlrp14. The molecular mechanism of there gulation of Lhx8 in the oocyte has not been described. We examined to characterize Lhx8 DNA binding elements and to identify its direct target genes in the oocyte. CAST was performed using glutathione transferase Lhx8 homeodomain fusion protein (GST-LHX8HD). A 15-bp random sequence flanked by 20-bp of fixed sequences were incubated with purified GST-LHX8HD protein. Unbound DNA was washed with binding reaction buffer. Bound DNA was eluted and re-amplified by PCR for the next round of CAST. Final PCR products were cloned and sequenced to derive consensus binding sequence. EMSA was performed using 32P-labeled oligomers. Binding reactions were conducted by incubating 32P-labeled probes with purified protein. Dual luciferase assays were carried out with extracts of total HEK293 cell which was transfected by the pGL4-promoter vector containing three artificial repeats of LBE(3xLBE-Luc) and overexpression vector carrying the Lhx8 homeodomain as recommended by Promega. We identified several cis-acting sites, TGATTG as Lhx8 DNA binding elements (LBE) using a library of randomly generated oligonucleotides by CAST. EMSA reslut shows that Lhx8 preferentially binds to the oligomer including Lhx8 binding element (TGATTG) with high affinity. In addition, we found that the relative luciferase activity of reporter construct containing three copies of TGATTG was increased by 2.3-fold with Lhx8 overexpression. These results suggest that Lhx8 preferentially binds Lhx8 DNA binding element, TGATTG, and can transactivate reporter genes through the LBE. The transcription of Lhx8 target gene in oocytes directly might be regulated by its during early folliculogenesis.