Abstract
B-cell lymphoma/leukaemia 11A (BCL11A) is a C2H2-type zinc-finger transcription factor protein that is a critical modulator of haemoglobin switching and suppresses the production of foetal haemoglobin. Variation in the BCL11A gene ameliorates the severity of sickle cell disease (SCD) and β-thalassemia (β-thal). The BCL11A gene is located on chromosome 2p16.1 and encodes an 835-amino acid protein.
Using state-of-the-art in silico tools, this study examined the most pathogenic non-synonymous single nucleotide polymorphisms (nsSNPs) that disrupt the BCL11A protein and mediate foetal-to-adult globin switching. A total of 11,463 SNPs were retrieved from the Single Nucleotide Polymorphism database (dbSNP). These included 799 in the 5' untranslated region (UTR), 486 in the 3' UTR, and 266 non-synonymous, 189 coding synonymous, six nonsense, and six stop-gained SNPs.
In silico tools (SIFT, SNAP, PolyPhen-2, PANTHER, I-Mutant, PROVEAN, SNPs&GO, mCSM, and PhD-SNP) predicted the five most-deleterious nsSNPs: rs61742690, rs62142605, rs17028351, rs115666026, and rs74987258. Molecular dynamic simulation and homology modelling of the mutated proteins (S783N, D643N, G451S, K670R, and M313L) of the most deleterious nsSNPs revealed their functional and structural impact. nsSNP rs61742690 was predicted to be the most deleterious, as supported by eight of the nine in silico tools.
Complete failure in the protein-protein interactions with functional partners (KLF1 and others) and significant changes (±100% variation) in the interface energy revealed that rs61742690 (S783N) in the zinc-finger domain is a suitable target for disrupting BCL11A-mediated foetal-to-adult globin switching.