Interactions of ribosomal protein S1 with DsrA and rpoS mRNA

Ribosomal protein S1 is shown to interact with the non-coding RNA DsrA and with rpoS mRNA. DsrA is a non-coding RNA that is important in controlling expression of the rpoS gene product in Escherichia coli. Photochemical crosslinking, quadrupole-time of flight tandem mass spectrometry, and peptide sequencing have identified an interaction between DsrA and S1 in the 30S ribosomal subunit. Purified S1 binds both DsrA (K(obs) approximately 6 x 10(6) M(-1)) and rpoS mRNA (K(obs) approximately 3 x 10(7) M(-1)). Ribonuclease probing experiments indicate that S1 binding has a weak but detectable effect on the secondary structure of DsrA or rpoS mRNA.     

TT8 controls its own expression in a feedback regulation involving TTG1 and homologous MYB and bHLH factors, allowing a strong and cell-specific accumulation of flavonoids in Arabidopsis thaliana

The control of TT8 expression was investigated in this study, and it was demonstrated that it constitutes a major regulatory step in the specific activation of the expression of flavonoid structural genes. First, the GUS activity generated in planta from a TT8::uidA construct revealed cell-specific activation of the TT8 promoter consistent with the known involvement of the TT8 bHLH factor in proanthocyanidin, anthocyanin and mucilage biosynthesis. Moreover, the activity of this reporter construct was strongly affected in ttg1, TT2 overexpressers (OE), and PAP1-OE, suggesting interplay between TT2, PAP1, TTG1 and the activation of the TT8 promoter in planta. To further investigate the mechanisms involved, we used 35S::TT2-GR and 35S::TTG1-GR transgenic plants (expressing fusion proteins with the glucocorticoid receptor), as well as one-hybrid experiments, to determine the direct effect of these factors on TT8 expression. Interestingly, in vivo binding of TT2 and PAP1 to the TT8 promoter was dependent on the simultaneous expression of TT8 or the homologous bHLH factors GL3 and EGL3. Consistent with these results, the activity of the TT8::uidA reporter was strongly affected in the seed endothelium of a tt8 mutant. Similarly, a strong decrease in the level of TT8 mRNA was detected in the siliques of a gl3 x egl3 mutant and in plants that express a dominant negative form of the PAP1 protein, suggesting that TT8 expression is controlled by different combinations of MYB and bHLH factors in planta. The importance of this positive feedback mechanism in the strong and specific induction of proanthocyanidin biosynthesis in the seed coat of Arabidopsis thaliana is discussed.     

Defects in the cerebella of conditional <Emphasis Type="Italic">Neurod1</Emphasis> null mice correlate with effective <Emphasis Type="Italic">Tg(Atoh1-cre)</Emphasis> recombination and granule cell requirements for <Emphasis Type="Italic">Neurod1</Emphasis> for differentiation

Neurod1 is a crucial basic helix-loop-helix gene for most cerebellar granule cells and mediates the differentiation of these cells downstream of Atoh1-mediated proliferation of the precursors. In Neurod1 null mice, granule cells die throughout the posterior two thirds of the cerebellar cortex during development. However, Neurod1 is also necessary for pancreatic β-cell development, and therefore Neurod1 null mice are diabetic, which potentially influences cerebellar defects. Here, we report a new Neurod1 conditional knock-out mouse model created by using a Tg(Atoh1-cre) line to eliminate Neurod1 in the cerebellar granule cell precursors. Our data confirm and extend previous work on systemic Neurod1 null mice and show that, in the central lobules, granule cells can be eradicated in the absence of Neurod1. Granule cells in the anterior lobules are partially viable and depend on as yet unknown genes, but the Purkinje cells show defects not previously recognized. Interestingly, delayed and incomplete Tg(Atoh1-cre) upregulation occurs in the most posterior lobules; this leads to near normal expression of Neurod1 with a concomitant normal differentiation of granule cells, Purkinje cells, and unipolar brush cells in lobules IX and X. Our analysis suggests that Neurod1 negatively regulates Atoh1 to ensure a rapid transition from proliferative precursors to differentiating neurons. Our data have implications for research on medulloblastoma, one of the most frequent brain tumors of children, as the results suggest that targeted overexpression of Neurod1 under Atoh1 promoter control may initiate the differentiation of these tumors. Ning Pan and Israt Jahan contributed equally to this paper. This work was supported by an NIH grant (R01 DC 005590) to B.F.     

The novel 5bp deletion polymorphism in the promoter region of bovine <Emphasis Type="Italic">ACRP30</Emphasis> gene

ACRP30 gene was located nearby the QTL affecting the marbling, ribeye muscle area and fat thickness on the BAT1 in Angus. In this study, a 5bp deletion mutation within the bovine ACRP30 gene was firstly detected and confirmed in 991 cattle by PCR-SSCP, DNA sequencing and direct PCR amplification. The deletion mutation was appeared in Qinchuan, Nanyang, Jiaxian and Hasake, but was not found in Jinnan, Chinese Holsteins and Angus. The association of the deletion polymorphism with growth traits (including birth weight, body weight, average daily gain and body sizes in different growth periods (6/12/18/24 month-old)) was analyzed in 224 Nanyang cattle. No signification association of the deletion polymorphism with growth traits were observed (P > 0.05). The deletion was located in the promoter region and it resulted in a new putative CCAAT/enhancer binding protein-β response element (C/EBP-RE).     

Teratological evaluation of mouse fetuses exposed to a 20 kHz EMF

As a continuation of our previous study, we performed a teratological evaluation of the importance of gestational age with regards to the exposure of 20 kHz intermediate frequency magnetic field (IF) on pregnant ICR mice. The pregnant mice were exposed to a 20 kHz IF magnetic field for 8 h/day in a carousel irradiator at 30 µT which is the limit standard for occupational population in Korea. The animals were sacrificed on the 18th day of gestation and the fetuses were examined for mortality, growth retardation, changes in head size and other morphological abnormalities. We concluded that exposure to 30 µT with 20 kHz IF did not cause any observable adverse effects on mouse fetuses. Bioelectromagnetics 30:330–333. © 2009 Wiley‐Liss, Inc.     

四环素调控A30P突变α-synuclein转基因小鼠的构建

为了构建四环素调控的人A30P突变α-synuclein转基因小鼠模型,将外源基因pTRE2-syn和pBC-rtTA同时显微注射到FVB小鼠(Mus muscculus)受精卵的雄原核中,将注射后存活的受精卵移植到同期发情的假孕受体鼠输卵管中,出生个体经PCR检测,获得rtTA和A30P突变α-synuclein双阳性转基因雌鼠1只,A30P单基因阳性雄鼠13只并传代.强力霉索诱导后双阳性后代脑区各部分A30P突变α-synucleinmRNA均有表达,而在诱导满4周后,脑干α-synuclein蛋白表达明显增加,8周后增加更明显.结果表明,通过强力霉素诱导后,可在小鼠小脑、脑干、海马、皮层检测到A30P mRNA表达,脑干α-synuclein表达量显著增加.