Search bioRxiv⌕ Search

Biology subjects

Thiam, A.

Publications and source records attributed to Thiam, A..

2 recordsLinked to original sources

Unraveling a novel dual-function regulatory element showing epistatic interaction with a variant that escapes genome-wide association studies.

Regulation of gene expression has recently been complexified by the identification of Epromoters, a subset of promoters with enhancer function. Here, we uncovered the first dual cis-regulatory element, "ESpromoter," exhibiting both enhancer and silencer function, as a regulator of the nearby genes ATP2B4 and LAX1 in single human T cells. Through integrative approach, we pinpointed functional rs11240391, a severe malaria risk variant that escapes detection in genome-wide association studies, challenging conventional strategies for identifying causal variants. CRISPR-modified cells demonstrated the regulatory effect of ESpromoter and rs11240391 on LAX1 expression and T cell activation. Furthermore, our findings revealed an epistatic interaction between ESpromoter SNPs and rs11240391, impacting severe malaria susceptibility by further reducing LAX1 expression. This groundbreaking discovery challenges the conventional enhancer-silencer dichotomy. It highlights the sophistication of transcriptional regulation and argues for an integrated approach combining genetics, epigenetics, and genomics to identify new therapeutic targets for complex diseases. HIGHLIGHTSO_LINovel dual enhancer-silencer element (ESpromoter) in a single human cell type C_LIO_LIFunctional SNP for severe malaria risk that escapes genome-wide association studies C_LIO_LIGenome editing at the SNP demonstrates a regulatory effect on LAX1 and T cell activation C_LIO_LIEpistatic interaction between SNPs increases the risk of severe malaria C_LI In briefEpistatic interaction between common variants within a novel dual enhancer-silencer regulatory element and the LAX1 promoter variant is responsible for severe malaria susceptibility through T-cell activation.

genomics↗

Gymnosiphon fonensis (Burmanniaceae) a new Critically Endangered species from Simandou, Republic of Guinea, W. Africa.

A new species of Gymnosiphon Blume (Burmanniaceae), G.fonensis Cheek is formally described from the Foret Classee de Pic de Fon, Simandou Range, Guinee-Forestiere, Republic of Guinea (Guinee-Conakry) in West Africa. The new species was formerly confused with and resembles G. bekensis Letouzey of central Africa in the broad flat outer tepal lobes, perianth tube >10 mm long, and (sub)sessile flower. It differs e.g. in that the length of the corolla tube, (13-)14-18 mm, exceeds the corolla diameter (10-11 mm) (vs length of the corolla tube (12 mm) < the corolla diameter (12-15 mm)), the anthers inserted c. 4 mm deep in the corolla tube (vs inserted at the corolla mouth) and the rhizome lacks scale-leaves (vs scale leaves present). Gymnosiphon fonensis is the first known species of its genus and family in which secondary pollen presentation has been recorded. The species is known from five sites, all with threats, in a single threat-based location, accordingly it is assessed as Critically Endangered (CR B1ab(iii)) using the IUCN 2012 standard, making it the most threatened species of Gymnosiphon in continental Africa. The new species is illustrated by colour photos and line-drawings and is mapped. An identification key is provided to the ten species of the genus now known from Africa-Madagascar.

plant biology↗