342 research outputs found
Chiral Current Algebras in Three--Dimensional Bf--Theory with Boundary
We consider the three--dimensional BF--model with planar boundary in the
axial gauge. We find two--dimensional conserved chiral currents living on the
boundary and satisfying Kac--Moody algebras.Comment: 18 page
The frequency of somatic mutations in cancer predicts the phenotypic relevance of germline mutations
Identification of candidate regulatory sequences in mammalian 3' UTRs by statistical analysis of oligonucleotide distributions
3' untranslated regions (3' UTRs) contain binding sites for many regulatory
elements, and in particular for microRNAs (miRNAs). The importance of
miRNA-mediated post-transcriptional regulation has become increasingly clear in
the last few years.
We propose two complementary approaches to the statistical analysis of
oligonucleotide frequencies in mammalian 3' UTRs aimed at the identification of
candidate binding sites for regulatory elements. The first method is based on
the identification of sets of genes characterized by evolutionarily conserved
overrepresentation of an oligonucleotide. The second method is based on the
identification of oligonucleotides showing statistically significant strand
asymmetry in their distribution in 3' UTRs.
Both methods are able to identify many previously known binding sites located
in 3'UTRs, and in particular seed regions of known miRNAs. Many new candidates
are proposed for experimental verification.Comment: Added two reference
The 2D effective field theory of interfaces derived from 3D field theory
The one--loop determinant computed around the kink solution in the 3D
theory, in cylindrical geometry, allows one to obtain the partition
function of the interface separating coexisting phases. The quantum
fluctuations of the interface around its equilibrium position are described by
a two--dimensional conformal field theory, namely a 2D free massless
scalar field living on the interface. In this way the capillary wave model
conjecture for the interface free energy in its gaussian approximation is
proved.Comment: latex, 9 pages, no figure
Computational identification of transcription factor binding sites by functional analysis of sets of genes sharing overrepresented upstream motifs
BACKGROUND: Transcriptional regulation is a key mechanism in the functioning
of the cell, and is mostly effected through transcription factors binding to
specific recognition motifs located upstream of the coding region of the
regulated gene. The computational identification of such motifs is made easier
by the fact that they often appear several times in the upstream region of the
regulated genes, so that the number of occurrences of relevant motifs is often
significantly larger than expected by pure chance. RESULTS: To exploit this
fact, we construct sets of genes characterized by the statistical
overrepresentation of a certain motif in their upstream regions. Then we study
the functional characterization of these sets by analyzing their annotation to
Gene Ontology terms. For the sets showing a statistically significant specific
functional characterization, we conjecture that the upstream motif
characterizing the set is a binding site for a transcription factor involved in
the regulation of the genes in the set. CONCLUSIONS: The method we propose is
able to identify many known binding sites in S. cerevisiae and new candidate
targets of regulation by known transcription factors. Its application to less
well studied organisms is likely to be valuable in the exploration of their
regulatory interaction network.Comment: 19 pages, 1 figure. Published version with several improvements.
Supplementary material available from the author
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