Biology subjects

Toure, A.

Publications and source records attributed to Toure, A..

3 recordsLinked to original sources

bioRxiv2023

Characterization of adaptation mechanisms in sorghum using a multi-reference back-cross nested association mapping design and envirotyping

The identification of haplotypes influencing traits of agronomic interest, with well-defined effects across environments, is of key importance to develop varieties adapted to their context of use. It requires advanced crossing schemes, multi-environment characterization and relevant statistical tools. Here we present a sorghum multi-reference back-cross nested association mapping (BCNAM) population composed of 3901 lines produced by crossing 24 diverse parents to three elite parents from West and Central Africa (WCA-BCNAM). The population was characterized in environments contrasting for photoperiod, rainfall, temperature, and soil fertility. To analyse this multi-parental and multi-environment design, we developed a new methodology for QTL detection and parental effect estimation. In addition, envirotyping data were mobilized to determine the influence of specific environmental covariables on the genetic effects, which allowed spatial projections of the QTL effects. We mobilized this strategy to analyse the genetic architecture of flowering time and plant height, which represent key adaptation mechanisms in environments like West Africa. Our results allowed a better characterisation of well-known genomic regions influencing flowering time concerning their response to photoperiod with Ma6 and Ma1 being photoperiod sensitive and candidate gene Elf3 being insensitive. We also accessed a better understanding of plant height genetic determinism with the combined effects of phenology dependent (Ma6) and independent (qHT7.1 and Dw3) genomic regions. Therefore, we argue that the WCA-BCNAM constitutes a key genetic resource to feed breeding programs in relevant elite parental lines and develop climate-smart varieties.

genetics↗

bioRxiv2023

Novel axonemal protein ZMYND12 is required for flagellum function and male fertility

Male infertility is common and complex, presenting a wide range of heterogeneous phenotypes. Although about 50% of cases are estimated to have a genetic component, the underlying cause often remains undetermined. Here, from whole-exome sequencing on samples from 168 infertile men with asthenoteratozoospermia due to severe sperm flagellum, we identified homozygous ZMYND12 variants in four unrelated patients. In sperm cells from these individuals, immunofluorescence revealed altered localization of DNAH1, DNALI1, WDR66 and TTC29. Axonemal localization of ZMYND12 ortholog TbTAX-1 was confirmed using the Trypanosoma brucei model. RNAi knock-down of TbTAX-1 dramatically affected flagellar motility, with a phenotype similar to the sperm from men bearing homozygous ZMYND12 variants. Co-immunoprecipitation and ultrastructure expansion microscopy in T. brucei revealed TbTAX-1 to form a complex with TTC29. Comparative proteomics with samples from Trypanosoma and Ttc29 KO mice identified a third member of this complex: DNAH1. The data presented revealed that ZMYND12 is part of the same axonemal complex as TTC29 and DNAH1, which is critical for flagellum function and assembly in humans, and Trypanosoma. ZMYND12 is thus a new asthenoteratozoospermia-associated gene, bi-allelic variants of which cause severe flagellum malformations and primary male infertility.

genetics↗

bioRxiv2022

MEIG1/PACRG associated and non-associated functions of axonemal dynein light intermediate polypeptide 1 (DNALI1) in mammalian spermatogenesis

Axonemal dynein light intermediate polypeptide 1 (DNALI1) was originally cloned from Chlamydomonas reinhardtii in an effort to find motor proteins essential for flagellar motility. Here we report that DNALI1 is a binding partner of parkin co-regulated gene 1 (PACRG), which forms a complex with meiosis expressed gene 1 (MEIG1) in the manchette, a transient and unique structure only present in the elongating spermatids and required for normal spermiogenesis of the male germ cell differentiation process. DNALI1 recruits the PACRG protein in transfected CHO cells, and also stabilizes PACRG in bacteria and transfected mammalian cells. The untagged DNALI1 could also be co-purified with His-tagged PACRG in the gel filtration assay. Immunofluorescence staining on isolated male germ cells revealed that DNALI1 was present in the manchette of elongating spermatids, and colocalized with PACRG in this structure. In Pacrg mutant mice, localization of DNALI1 in the manchette was not changed, suggesting that DNALI1 and PACRG form a complex in the manchette, with DNALI1 being an upstream molecule. Mice deficiency in DNALI1 specifically in male germ cells showed dramatically reduced sperm numbers and were infertile. In addition, majority of the sperm exhibited abnormal morphology including misshapen heads, bent tails and enlarged midpiece, discontinuous accessory structure, and loss of sperm individualization, emphasizing the importance of DNALI1 in sperm development. Examination of testis histology revealed impaired spermiogenesis in the conditional Dnali1 knockout mice. Electron microscopy revealed disrupted ultrastructure in sperm of the Dnali1 mutant mice. Testicular levels of MEIG1, PACRG and SPAG16L proteins were not changed in the Dnali1 mutant mice. However, MEIG1 and SPAG16L were no longer present in the manchette in the absence of DNALI1. These findings demonstrate that DNALI1 is involved in the connection of the MEIG1/PACRG complex to carry cargo proteins along the manchette microtubules for sperm flagella formation. Given that Dnali1 mutant mice showed impaired sperm individualization that was not observed in the MEIG1 nor PACRG-deficient mice, DNALI1 might fulfill other functions beyond its role associated with the MEIG1/PACRG complex. Thus, DNALI1 plays multiple roles in sperm cell differentiation and function. Summary statementAxonemal dynein light intermediate polypeptide 1 (DNALI1) is required for sperm formation and male fertility. It associates with the MEIG1/PACRG complex in the manchette and is involved in a cargo transport system. In addition, it might be related to IFT and sperm individualization.

cell biology↗