Molecular characterization of exons 6, 8 and 9 of ABCB4 gene in children with Progressive Familial Intrahepatic Cholestasis type 3

Molecular Modelling and Evaluation of Hidden Information in ABCB11 Gene Mutations

BACKGROUND

Cholestatic disorders are divided in the extra and intra-hepatic that created due to the severe liver diseases. ABCB11 encodes the bile salt export pump and this gene is mutated in several forms of intrahepatic cholestasis. So far, some molecular features of this gene was studies.

OBJECTIVE

Using a developed web server, we identified high number of rare codons in this gene, and four cases were related to BSEP-deficient patients which can be used for drug design.

MATERIAL AND METHODS

By in-silico modelling of ABCB11, some of rare codons in different locations of ATP8b1 gene were identified and evaluated. Using several web servers a number of mutations that converted non-rare codons to rare codon in these patients were identified.

RESULTS

Some of these rare Codons were located at special positions by mutation of which, the new side chains do not seem suitable for protein structure and function. Furthermore, this mutation changed the protein folding rate that may have a critical role in proper folding. Thus, primary change of these codons contributes to BSEP deficiency.

CONCLUSION

This work is a comprehensive analysis of rare codons of ABCB11 and assessment of a number of these rare codon in protein levels. Rare codons evaluation can enhance our understanding of ABCB11 structural protein of ABCB11, and help us to develop mutation-specific therapies in design of new drugs.

D, F. E, M.R. F, M. M, S.M.B. T. In-silico Evaluation of Rare Codons and their Positions in the Structure of ATP8b1 Gene

BACKGROUND

Progressive familial intrahepatic cholestases (PFIC) are a spectrum of autosomal progressive liver diseases developing to end-stage liver disease. ATP8B1 deficiency caused by mutations in ATP8B1 gene encoding a P-type ATPase leads to PFIC1. The gene for PFIC1 has been mapped on a 19-cM region of 18q21-q22, and a gene defect in ATP8B1 can cause deregulations in bile salt transporters through decreased expression and/or activity of FXR. Point mutations are the most common, with the majority being missense or nonsense mutations. In addition, approximately 15% of disease-causing ATP8B1 mutations are annotated as splicing disrupting alteration given that they are located at exon-intron borders.

OBJECTIVE

Here, we describe the hidden layer of computational biology information of rare codons in ATP8B1, which can help us for drug design.

METHODS

Some rare codons in different locations of ATP8b1 gene were identified using several web servers and by in-silico modelling of ATP8b1 in Phyre2 and I-TASSER server, some rare codons were evaluated.

RESULTS

Some of these rare codons were located at special positions which seem to have a critical role in proper folding of ATP8b1 protein. Structural analysis showed that some of rare codons are related to mutations in ATP8B1 that are responsible for PFIC1 disease, which may have a critical role in ensuring the correct folding.

CONCLUSION

Investigation of such hidden information can enhance our understanding of ATP8b1 folding. Moreover, studies of these rare codons help us to clarify their role in rational design of new and effective drugs.