# HG changeset patch # User mkhan1980 # Date 1362397078 18000 # Node ID e3c4e5ff7f74e1e6fa40e41701e433fcddd70337 # Parent ebad609b8a6d7c0032a0b0798f758f42eef309fe Uploaded diff -r ebad609b8a6d -r e3c4e5ff7f74 check.xml --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/check.xml Mon Mar 04 06:37:58 2013 -0500 @@ -0,0 +1,43 @@ + + + check.pl $input $input2 $output + + + + + + + + + + + + + + + + + + + +Background: +This tool computationally predicts CTCF sites for a nucleotide sequence located on the forward strand. The user is required to provide two files as inputs. The first is the nucleotide sequence of interest on the + strand in FASTA format (this can be obtained from UCSC genome browser or Ensembl). The second file must be a FASTA formatted file containing the chromosome number and the genomic position of the first nucleotide sequence (separated by a tab). For example, if the sequence of interest is located on chromosome 3 with a starting genomic position of 1850000, the first line of the second input file must start with a fasta tag, and the second line will be chr3 1850000 + +Details of Algorithm: +CTCF sites are predicted by applying the following equation +w(σ,j) = log2 (((f(σ,j) + sqrt(N) x b(σ)) / (N + sqrt(N))) / b(σ)) + +Where w(σ,j) is the weight of nucleotide σ at position j, N is the total number of binding sites or the sum of all nucleotide occurrences in the column, and b is the prior background frequency of the nucleotide σ. + +The sum of weights for corresponding nucleotides at each column of the matrix then estimates the likelihood of any sequence of length m to be an instance of a CTCF binding site and takes into account the GC content of the genomic region being scanned. + + +Citation and further help: For further details of the algorithm, please refer to + +Khan MA, Soto-Jimenez LM, Howe T, Streit A, Sosinsky A, Stern CD (2013). Computational tools and resources for prediction and analysis of gene regulatory regions in the chick genome.. Genesis, , - . doi:10.1002/dvg.22375 + +For queries/questions, email ucbtmaf@ucl.ac.uk + + + +