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Different Cis (different + cis)

Distribution by Scientific Domains

Life Sciences	50%
Chemistry	50%

Selected Abstracts

Frontal nasal prominence expression driven by Tcfap2a relies on a conserved binding site for STAT proteins

DEVELOPMENTAL DYNAMICS, Issue 5 2006
Amy L. Donner
Abstract The AP-2 transcription factor family is linked with development of the head and limbs in both vertebrate and invertebrate species. Recent evidence has also implicated this gene family in the evolution of the neural crest in chordates, a critical step that allowed the development and elaboration of the vertebrate craniofacial skeleton. In mice, the inappropriate embryonic expression of one particular AP-2 gene, Tcfap2a, encoding AP-2,, results in multiple developmental abnormalities, including craniofacial and limb defects. Thus, Tcfap2a provides a valuable genetic resource to analyze the regulatory hierarchy responsible for the evolution and development of the face and limbs. Previous studies have identified a 2-kilobase intronic region of both the mouse and human AP-2, locus that directs expression of a linked LacZ transgene to the facial processes and the distal mesenchyme of the limb bud in transgenic mice. Further analysis identified two highly conserved regions of ,200,400 bp within this tissue-specific enhancer. We have now initiated a transgenic and biochemical analysis of the most important of these highly conserved regions. Our analysis indicates that although the sequences regulating face and limb expression have been integrated into a single enhancer, different cis -acting sequences ultimately control these two expression domains. Moreover, these studies demonstrate that a conserved STAT binding site provides a major contribution to the expression of Tcfap2a in the facial prominences. Developmental Dynamics 235:1358,1370, 2006. © 2006 Wiley-Liss, Inc. [source]

Photoregulation of DNA transcription by using photoresponsive T7 promoters and clarification of its mechanism

FEBS JOURNAL, Issue 6 2010
Xingguo Liang
With the use of photoresponsive T7 promoters tethering two 2,-methylazobenzenes or 2,,6,-dimethylazobenzenes, highly efficient photoregulation of DNA transcription was obtained. After UV-A light irradiation (320,400 nm), the rate of transcription with T7 RNA polymerase and a photoresponsive promoter involving two 2,,6,-dimethylazobenzenes was 10-fold faster than that after visible light irradiation (400,600 nm). By attaching a nonmodified azobenzene and 2,,6,-dimethylazobenzene at the two positions, respectively, and by utilizing the different cis,trans thermal stability between cis -nonmodified azobenzene and cis- 2,,6,-dimethylazobenzene, four species of T7 promoter (cis,cis, trans,cis, cis,trans, and trans,trans) were obtained. The four species showed transcriptional activity in the order of cis,cis > cis,trans > trans,cis > trans,trans. Kinetic analysis revealed that the Km for the cis,cis promoter (both of the introduced azobenzene derivatives were in the cis form) and T7 RNA polymerase was 68 times lower than that for the trans,trans form, indicating that high photoregulatory efficiency was mainly due to a remarkable difference in affinity for RNA polymerase. The present approach is promising for the creation of biological tools for artificially controlling gene expression, and as a photocontrolled system for supplying RNA fuel for RNA-powered molecular nanomachines. [source]

Functional analysis of the cis -acting elements responsible for the induction of the Cyp6a8 and Cyp6g1 genes of Drosophila melanogaster by DDT, phenobarbital and caffeine

INSECT MOLECULAR BIOLOGY, Issue 1 2010
R. Morra
Abstract Many Drosophila cytochrome P450 or Cyp genes are induced by caffeine and phenobarbital (PB). To understand the induction mechanism, we created Drosophila S2 cell lines stably transformed with different luciferase reporter plasmids carrying upstream DNAs of Cyp6a8 allele of the resistant 91-R strain, and the 1.1-kb upstream DNAs of Cyp6g1 of the 91-R and the susceptible 91-C strains. Following 24 h treatment with dichlorodiphenyltrichloroethane (DDT), caffeine or PB, luciferase activity of all cell lines was determined. Results showed that the 0.1-kb DNA of Cyp6a8 and the upstream DNAs of Cyp6g1 from both strains are not induced by these chemicals in S2 cells. However, the 0.2-, 0.5- and 0.8-kb DNAs of Cyp6a8 showed 13,24-, 4,5- and 2.2,2.7-fold induction with caffeine, PB and DDT, respectively. These DNAs also showed a 2,3-fold synergistic effect of caffeine and PB but not of caffeine and DDT. The results suggest that the cis -regulatory elements for all three chemicals are located within the -11/-199 DNA of Cyp6a8. Furthermore, caffeine and PB inductions appear to be mediated via different cis -elements, whereas caffeine and DDT induction may involve common regulatory elements. These stably transformed cell lines should help understand the mechanism of resistance-associated Cyp gene overexpression in Drosophila. [source]

Poly[(,6 - rac - cis -cyclohexane-1,2-dicarboxylato)strontium]

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2010
Karen A. Robertson
In the title layered coordination polymer, [Sr(C8H10O4)]n, the strontium ion adopts a distorted square-antiprismatic SrO8 geometry, arising from its coordination by six different cis -cyclohexane-1,2-dicarboxylate dianions (two bidentate and four monodentate). Within the dianion, the cyclohexane ring adopts a chair conformation and the dihedral angle between the planes of the ,CO2, groups is 80.4,(6)°. The polyhedral linkage pattern leads to (100) sheets in the crystal in which the SrO8 groups share triangular faces and edges in which the Sr...Sr topological connectivity is a 63 net. The crystal studied was a nonmerohedral twin, with the components related by a 180° rotation about [100]. [source]