NuPose: Nucleosome positioning based on DNA sequence

A guideline for ResNuc

ResNuc is a software package to predict the position of nucleosomes and includes a web-based platform and a standalone version. The web-based version of ResNuc has been developed using the Django web development platform and Keras machine learning library and consists of four main parts (Figure 1). The first part comprises two datasets associated with the nucleosome positioning information and extracted features. These datasets can be downloaded and used in computational biology-based projects (Figure 2).

Figure 1: The overall schematic of ResNuc’s web-based platform

Figure 2: The dataset section of ResNuc’s web-based platform
The second part of the web-based platform, single nucleosome positioning prediction (SNPP), receives at most 500 201-bp DNA sequences (FASTA format) and predicts their nucleosome positioning capabilities. To this end, the given sequences are extracted from the input, and, then, their features are extracted. Next, they are passed to the prediction model and are labeled with a probability value indicating how much a specific DNA sequence can be occupied by a histone octamer. Although the generated prediction model can be applied to the smaller DNA fragments, it is advised to use 201-bp DNA fragments. Figure 3 displays the SNPP section of ResNuc.

Figure 3: The SNPP section of ResNuc’s web-based platform
The third part of the web-based platform searches for the position of nucleosomes in a given long-size DNA sequence (MNPP). For this purpose, ResNuc divides the sequence into 201-bp fragments and then calls the generated prediction model. Like SNPP, due to high computational complexity, the web version of MNPP has been limited to 700 bp DNA sequences. For larger sequences, the standalone version be utilized. Figure 4 shows the MNPP part of the web-based platform.

Figure 4: The MNPP section of ResNuc’s web-based platform
After calling ResNuc, the prediction page appears, which shows the predicted positioning scores (Figure 5). At the bottom section of the page, there is a download button, by which users can get a copy of the predicted results as a text-format file and use it for further analysis. This file includes 3 slices for every record: (i) the row number, (ii) the position’s number/the DNA fragment’s name, and (ii) the positioning score.

Figure 5: An instance of the results section



About Panchenko's lab

We study the associations between key components in the epigenome to understand how its perturbation can lead to cancer. Our team works to identify factors contributing to cancer mutation occurrence in DNA, to discover molecular mechanisms of how mutations and covalent modifications affect nucleosomes and chromatin, their interactions, stability and dynamics.

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