Ipsographing the Dubject; or, The Contradictions of Twitter

Precise control of self-renewal and differentiation of progenitor cells into the cranial neural crest (CNC) pool ensures proper head development, guided by signaling pathways such as BMPs, FGFs, Shh and Notch. Here, we show that murine Sox2 plays an essential role in controlling progenitor cell behavior during craniofacial development. A "Conditional by Inversion" Sox2 allele (Sox2(COIN) ) has been employed to generate an epiblast ablation of Sox2 function (Sox2(EpINV) ). Sox2 (EpINV/+(H)) haploinsufficient and conditional (Sox2(EpINV/mosaic) ) mutant embryos proceed beyond gastrulation and die around E11. These mutant embryos exhibit severe anterior malformations, with hydrocephaly and frontonasal truncations, which could be attributed to the deregulation of CNC progenitor cells during their epithelial to mesenchymal transition. This irregularity results in an exacerbated and aberrant migration of Sox10(+) NCC in the branchial arches and frontonasal process of the Sox2 mutant embryos. These results suggest a novel role for Sox2 as a regulator of the epithelial to mesenchymal transitions (EMT) that are important for the cell flow in the developing head

Synchronous Optical Network and Asynchronous Transfer Mode (ATM). The disadvantages

In this paper, a consideration about the notions of “virtual classroom ” and “virtual education” is forwarded. Although, most of the current tele-education systems use ISDN (Integrated Services Digital Networks) and satellite lines, the successful development of tele-education services depends on the deployment of high-speed networks to transfer multimedia traffic. In this article, dominant network technologies which are used as infrastructure for tele-education systems are presented. These technologies are: Frame Relay, Distributed Queue Dual Bus, Switched Multi-Megabit Data Service, Fibre Distributed Data Interface, FDDI-II

<i>Sox2^COIN</i> is a functional conditional allele.

<p>(<b>A</b>) Efficient removal of the <i>neo</i> cassette by Flpe recombinase to generate a <i>Sox2^COIN/+</i> allele. <i>Sox2^+/+</i> (lane 1), <i>Sox2^COIN/+</i> (lane 2), <i>Sox2^COIN/COIN</i> (lane 3), <i>Sox2^INV/+</i> (lane 4), <i>Sox2^βgeo2/+</i> (lane 5) E14.5 mice. PCR genotyping of (1) <i>Sox2^+/+</i>, (2) <i>Sox2^COIN/+ Tg(ACTB:FLPe)</i>, (3) <i>Sox2^COINneo/+</i>, (4) <i>Sox2^COIN/+</i>. (<b>B</b>) PCR genotyping of <i>Sox2^+/+</i> (lane 1), <i>Sox2^COIN/+</i> (lane 2), <i>Sox2^COIN/COIN</i> (lane 3) (genomic DNA from tail biopsies). (<b>C</b>) E14.5 <i>Sox2^COIN/COIN</i> embryos are morphologically indistinguishable from <i>Sox2^+/+</i> and <i>Sox2^COIN/+</i>. (<b>D</b>) Efficient inversion of the COIN module to generate <i>Sox2^INV/+</i> mice. PCR-based genotyping of (1) <i>Sox2^+/+</i> and (2) <i>Sox2^INV/+</i> (genomic DNA from tail biopsies). (<b>F, G</b>) <i>Sox2</i> and <i>Sox2ot</i> qPCR analysis in <i>Sox2^+/+</i>, <i>Sox2^COIN/+</i>, <i>Sox2^COIN/COIN</i>, <i>Sox2^βgeo2/+</i> and <i>Sox2^INV/+</i> E14.5 embryos. Cyclophilin was used as a control label. Data are presented as the mean<u>+</u>SEM (n = 3–6) for each genotype. The COIN module does not affect expression of <i>Sox2</i> prior to inversion. Additionallly, the COIN module does not appear to affect the expression level of <i>Sox2ot</i> either in <i>Sox2^COIN/COIN</i> or in <i>Sox2^INV/+</i> embryos. (<b>H</b>) <i>MiR1897</i> qPCR analysis in <i>Sox2^+/+</i>, <i>Sox2^COIN/+</i>, <i>Sox2^COIN/COIN</i>, <i>Sox2^βgeo2/+</i> and <i>Sox2^INV/+</i> E14.5 embryos. (<b>I</b>) Sox2 protein analysis. Western blot showing Sox2 and eGFP protein detected with specific antibodies in whole protein extracts from <i>Sox2^+/+</i>, <i>Sox2^COIN/+</i>, <i>Sox2^COIN/COIN</i>, <i>Sox2^βgeo2/+</i>, and <i>Sox2^INV/+</i> E14.5 embryos. The COIN module does not affect Sox2 protein levels prior to inversion.</p

Analysis of progeny from <i>Sox2^INV/+</i> × <i>Sox2^+/+</i> intercrosses^#.

<p>Genotyping of <i>Sox2^INV/+</i> heterozygous intercross progeny.</p>#<p>Data collected from mice in C57BL6 background.</p>*<p>Genotypes were assessed by PCR either from tail biopsies or whole embryos.</p

Analysis of progeny from <i>Sox2</i>^COIN/+ intercrosses^#.

<p>Genotyping of <i>Sox2</i>^COIN/+ heterozygous intercross progeny.</p>#<p>Data collected from mice in C57BL6 background.</p>*<p>Genotypes were assessed by PCR of genomic tail DNA.</p

Targeting strategy generating a COIN allele of <i>Sox2</i>.

<p>(<b>A</b>) Schematic representation of the mouse <i>Sox2</i> locus indicating the relative location of the exon on chromosome 3, as well as that of <i>mir1897</i>, the non-coding RNA <i>Sox2ot</i>, and CpG islands in the genomic region. The degree of conservation of the locus sequence between mammalian species (ECRs) is indicated. Adapted from <a href="http://genome.ucsc.edu" target="_blank">http://genome.ucsc.edu</a>. (<b>B</b>) Schematic representation of the <i>Sox2^COIN</i> allele. The COIN module intron is inserted after the 30^th nucleotide of <i>Sox2</i>’s coding region (i.e. coordinate 34549367 on Chromosome 3) splitting the single exon of Sox2 into two exons and also dividing the CpG island. The COIN module is comprised of an optimized gene trap-like element composed of the 3′ splice region of the rabbit beta globin gene (HBB_RABIT), followed by <i>eGFP</i> (lacking an initiating ATG) and the polyadenylation region from HBB_RABIT, all placed in the antisense strand. The COIN module has been flanked with <i>Lox71</i> and <i>Lox66</i> sites in a mirror image orientation, thereby enabling inversion by Cre. For BHR and targeting, a FRT-flanked <i>neo</i> cassette has been incorporated into the COIN intron. After targeting, <i>neo</i> is removed to give rise to the <i>Sox2^COIN</i> allele. The COIN module is antisense to <i>Sox2</i>, and hence it predicted not to interfere with expression of <i>Sox2</i>. However, after inversion of the COIN module to the sense strand, transcription terminates around the polyadenylation region of the COIN module, and as a result expression of <i>Sox2</i> is replaced by <i>eGFP</i>.</p