A Zebrafish Forebrain-Specific Zinc Finger Gene Can Induce Ectopic dlx2 and dlx6 Expression

AbstractIdentification of the earliest forebrain-specific markers should facilitate the elucidation of molecular events underlying vertebrate forebrain determination and specification. Here we report the sequence and characterization of fez (forebrain embryonic zinc finger), a gene that is specifically expressed in the embryonic forebrain of zebrafish. Fez encodes a putative nuclear zinc finger protein that is highly conserved in Drosophila, zebrafish, Xenopus, mouse, and human. In zebrafish, the expression of fez becomes detectable at the anterior edge of the presumptive neuroectoderm by 70% epiboly. During the segmentation period, its expression is completely restricted to the rostral region of the prospective forebrain. At approximately 24 h postfertilization, fez expression is mostly confined to the telencephalon and the anterior–ventral region of the diencephalon. Although fez expression is present in one-eyed pinhead (oep) and cyclops (cyc) zebrafish mutants, the pattern is altered. Forced expression of fez induces ectopic expression of dlx2 and dlx6, two genes involved in brain development. Knockdown of fez function using a morpholino-based antisense oligo inhibited dlx2 expression in the ventral forebrain. Our studies indicate that fez is one of the earliest markers specific for the anterior neuroectoderm and it may play a role in forebrain development by regulating Dlx gene expression

Peripheral blood gene expression reveals an inflammatory transcriptomic signature in Friedreich's ataxia patients.

Transcriptional changes in Friedreich's ataxia (FRDA), a rare and debilitating recessive Mendelian neurodegenerative disorder, have been studied in affected but inaccessible tissues-such as dorsal root ganglia, sensory neurons and cerebellum-in animal models or small patient series. However, transcriptional changes induced by FRDA in peripheral blood, a readily accessible tissue, have not been characterized in a large sample. We used differential expression, association with disability stage, network analysis and enrichment analysis to characterize the peripheral blood transcriptome and identify genes that were differentially expressed in FRDA patients (n = 418) compared with both heterozygous expansion carriers (n = 228) and controls (n = 93 739 individuals in total), or were associated with disease progression, resulting in a disease signature for FRDA. We identified a transcriptional signature strongly enriched for an inflammatory innate immune response. Future studies should seek to further characterize the role of peripheral inflammation in FRDA pathology and determine its relevance to overall disease progression

A highly conserved regulatory element controls hematopoietic expression of GATA-2 in zebrafish

<p>Abstract</p> <p>Background</p> <p>GATA-2 is a transcription factor required for hematopoietic stem cell survival as well as for neuronal development in vertebrates. It has been shown that specific expression of <it>GATA-2 </it>in blood progenitor cells requires distal <it>cis</it>-acting regulatory elements. Identification and characterization of these elements should help elucidating transcription regulatory mechanisms of <it>GATA-2 </it>expression in hematopoietic lineage.</p> <p>Results</p> <p>By pair-wise alignments of the zebrafish genomic sequences flanking <it>GATA-2 </it>to orthologous regions of fugu, mouse, rat and human genomes, we identified three highly conserved non-coding sequences in the genomic region flanking <it>GATA-2</it>, two upstream of <it>GATA-2 </it>and another downstream. Using both transposon and bacterial artificial chromosome mediated germline transgenic zebrafish analyses, one of the sequences was established as necessary and sufficient to direct hematopoietic GFP expression in a manner that recapitulates that of <it>GATA-2</it>. In addition, we demonstrated that this element has enhancer activity in mammalian myeloid leukemia cell lines, thus validating its functional conservation among vertebrate species. Further analysis of potential transcription factor binding sites suggested that integrity of the putative HOXA3 and LMO2 sites is required for regulating <it>GATA-2/GFP </it>hematopoietic expression.</p> <p>Conclusion</p> <p>Regulation of <it>GATA-2 </it>expression in hematopoietic cells is likely conserved among vertebrate animals. The integrated approach described here, drawing on embryological, transgenesis and computational methods, should be generally applicable to analyze tissue-specific gene regulation involving distal DNA <it>cis</it>-acting elements.</p

A Large-Scale Zebrafish Gene Knockout Resource for the Genome-Wide Study of Gene Function

With the completion of the zebrafish genome sequencing project, it becomes possible to analyze the function of zebrafish genes in a systematic way. The first step in such an analysis is to inactivate each protein-coding gene by targeted or random mutation. Here we describe a streamlined pipeline using proviral insertions coupled with high-throughput sequencing and mapping technologies to widely mutagenize genes in the zebrafish genome. We also report the first 6144 mutagenized and archived F1’s predicted to carry up to 3776 mutations in annotated genes. Using in vitro fertilization, we have rescued and characterized ~0.5% of the predicted mutations, showing mutation efficacy and a variety of phenotypes relevant to both developmental processes and human genetic diseases. Mutagenized fish lines are being made freely available to the public through the Zebrafish International Resource Center. These fish lines establish an important milestone for zebrafish genetics research and should greatly facilitate systematic functional studies of the vertebrate genome

Pur alpha and Sp8 as opposing regulators of neural gata2 expression

AbstractGata2 is an essential hematopoietic transcriptional factor that is also expressed prominently in the nervous system. The early lethality of knockout mice due to severe anemia has largely precluded studies of gata2 neural regulation and function. In this report, we describe the identification of zebrafish Pur alpha and Sp8 orthologs as two factors that function to regulate neuronal expression of gata2. During embryogenesis, Pur alpha is expressed widely, whereas Sp8 has an overlapping pattern of expression with gata2 in the nervous system. Knockdown and ectopic expressions of Pur alpha and Sp8 indicate that these factors function, respectively, as a repressor and an activator of gata2 gene expression in the nervous system. With consideration given to the previously established roles for these factors, we propose a model for how the transcriptional regulation of neural gata2 expression may be involved in controlling cellular proliferation in the nervous system

Detection of Citrus yellow vein clearing virus by Quantitative Real-time RT-PCR

To develop a rapid and reliable detection method for Citrus yellow vein clearing virus (CYVCV), a quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) system based on SYBR Green I was established by using a pair of specific primers designed from its conserved coat protein gene. The sensitivity, specificity, and applicability of the system were evaluated accordingly. The results showed that amplicons were produced from CYVCV isolates, whereas no amplicons from non-CYVCV citrus virus samples, including Citrus tristeza virus (CTV) and Citrus tatter leaf virus (CTLV), were obtained. The sensitivity of the qRT-PCR was 100-fold higher than that of conventional RT-PCR. An excellent linear correlation (R2 = 0.999) was obtained from two standard curves of cRNA, and the amplification efficiency was 102%. The data from field citrus samples detection showed that the qRT-PCR system could be used in determining the concentration of CYVCV in different citrus species

The coupled cooling effect of ventilation and spray in the deep-buried high-temperature tunnel

The utilization of ventilation and spray cooling technology is becoming increasingly popular in high-temperature workplaces due to its convenience and environmental friendliness. To investigate the coupled cooling effect of ventilation and spray in a construction tunnel, we established a droplet evaporation model under convective heat transfer conditions by combining the convective heat transfer theory and the droplet heat and mass transfer model. Based on this model, the study focused on the energy change of droplet evaporation in a moving medium by using numerical simulation in the context of a railroad construction tunnel. The material of the droplets used in the study was water. According to the simulation and field measurement results, it was obtained that, firstly, increased air volume of the tunnel and reduced airflow temperature could make the convective heat exchange stronger between the airflow and the wall. Secondly, the particle size of droplets formed by spraying was mainly 30–40 μm in the tunnel. A part of the droplets was evaporated in the high-temperature environment, and another part was trapped by the rock wall and ground. Third, adopting the coupled cooling method of ventilation and spray, the temperature and humidity fields in the tunnel changed significantly, and a low-temperature and high-humidity zone appeared near the nozzle. At the same time, the evaporation rate of droplets increased, the heat index of the workplace decreased, and the cooling effect was effective. Therefore, the coupled cooling method of ventilation and spray can effectively improve the thermal environment in high-temperature construction tunnels and enhance the thermal comfort of personnel. This study serves as a reference for the parameters and cooling effect of ventilation and spray cooling systems in construction sites

Effects of Different Row Ratios of Male and Female Parents and Application Amount of Nitrogen Fertilizer on Hybrid Wheat Seed Production and Its Component Factors

In order to screen suitable high hybrid wheat seed production technology, the split-plot experiment design was adopted and study was carried out about the effects of the different row ratios of male and female parents and application amount of nitrogen fertilizer on hybrid wheat seed production and its component factors. The results showed that the seed production increased with the increase in the number of female parent row. When the row ratio of male and female parents was 2:6, the seed production was 3 683.8 kg/ha; when the application amount of nitrogen fertilization was 50 kg/ha, the seed production was 3 649.4 kg/ha; the interaction between the row ratio of male and female parents and the application amount of nitrogen fertilizer indicated that when the row ratio of male and female parents was 2:6 and the application amount of nitrogen fertilizer was 300 kg/ha, the seed production reached the highest (4 160.6 kg/ha). The row ratio of male and female parents and application amount of nitrogen fertilizer had significant effect on the component factors of seed production, including the number of grains per spike, spike weight and setting percentage. When the row ratio of male and female parents was 2:5, the number of grains per spike, spike weight and setting percentage were the highest at 26.7 grains, 1.12 g, and 62.6% respectively; when application amount of nitrogen fertilizer was 450 kg/ha, the number of grains per spike, spike weight and setting percentage were the highest at 26.0 grains, 1.08 g, and 59.2% respectively; the interaction of row ratio of male and female parents and application amount of nitrogen fertilizer had significant effect on the number of grains per spike, spike weight and setting percentage; when the row ratio of male and female parents was 2:5 and the application amount of nitrogen fertilizer was 300 kg/ha, the number of grains per spike, spike weight and setting percentage were the highest at 29.6 grains, 1.24 g, and 71.6% respectively. Conclusions: the number of grains per spike is the largest component factor for seed production. Increasing the number of grains per spike can increase the seed production. According to the effects of row ratio of male and female parents and application amount of nitrogen fertilizer on the component factors of seed production, the optimal condition was 2:5-2:6 for row ratio of male and female parents and 300-450 kg/ha for application amount of nitrogen fertilizer