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Papers by France Leveille

Research paper thumbnail of The nuclear accumulation of the Fanconi anemia protein FANCE depends on FANCC

Research paper thumbnail of Estimating the effect-size of gene dosage on cognitive ability across the coding genome

Rare genomic Copy Number Variants (CNVs) are major contributors to neurodevelopmental disorder. T... more Rare genomic Copy Number Variants (CNVs) are major contributors to neurodevelopmental disorder. The vast majority of pathogenic CNVs reported back to patients are ultra-rare and their quantitative effects on traits such as intelligence are undocumented. Here, we identified all CNVs ≥ 50 kilobase in 24,092 individuals from unselected and autism cohorts. We developed statistical models to estimate the effect-size of CNVs on intelligence based on their coding and non-coding characteristics. Measures of intolerance to haploinsufficiency best explained the effect of any deletion or duplication on general intelligence. There was no heterogeneity across unselected and autism cohorts. Validation was performed using an intraclass concordance and showed that model estimates of general intelligence were 78% accurate with mean effect-sizes previously published for 47 CNVs. Inheritance data on 27,766 CNVs showed that deletions and duplications with the same large effect-size on intelligence occur de novo at the same frequency. Our first outline for the effect sizes of all coding genes on intelligence suggests that around 10,000 genes affect this trait.

Research paper thumbnail of NUP98-BPTF gene fusion identified in primary refractory acute megakaryoblastic leukemia of infancy

Genes, chromosomes & cancer, Jun 1, 2018

The advent of large scale genomic sequencing technologies significantly improved the molecular cl... more The advent of large scale genomic sequencing technologies significantly improved the molecular classification of acute megakaryoblastic leukaemia (AMKL). AMKL represents a subset (∼10%) of high fatality pediatric acute myeloid leukemia (AML). Recurrent and mutually exclusive chimeric gene fusions associated with pediatric AMKL are found in 60%-70% of cases and include RBM15-MKL1, CBFA2T3-GLIS2, NUP98-KDM5A and MLL rearrangements. In addition, another 4% of AMKL harbor NUP98 rearrangements (NUP98r), with yet undetermined fusion partners. We report a novel NUP98-BPTF fusion in an infant presenting with primary refractory AMKL. In this NUP98r, the C-terminal chromatin recognition modules of BPTF, a core subunit of the NURF (nucleosome remodeling factor) ATP-dependent chromatin-remodeling complex, are fused to the N-terminal moiety of NUP98, creating an in frame NUP98-BPTF fusion, with structural homology to NUP98-KDM5A. The leukemic blasts expressed two NUP98-BPTF splicing variants, co...

Research paper thumbnail of The Fanconi Anemia Gene Product FANCF Is a Flexible Adaptor Protein

Journal of Biological Chemistry, 2004

The Fanconi anemia (FA) protein FANCF is an essential component of a nuclear core complex that pr... more The Fanconi anemia (FA) protein FANCF is an essential component of a nuclear core complex that protects the genome against chromosomal instability, but the specific function of FANCF is still poorly understood. Based upon the homology between human and Xenopus laevis FANCF, we carried out an extensive mutagenesis study to examine which domains are functionally important and to gain more insight into the function of FANCF. In contrast to previous suggestions, we show that FANCF does not have a ROM-like function. We found that the C terminus of FANCF interacts directly with FANCG and allows the assembly of other FA proteins into a stable complex. The N terminus appears to stabilize the interaction with FANCA and FANCG and is essential for the binding of the FANCC/FANCE subcomplex. We identified several important amino acids in this N-terminal region but, surprisingly, many amino acid changes failed to affect the function of the FANCF protein. Our data demonstrate that FANCF acts as a flexible adaptor protein that plays a key role in the proper assembly of the FA core complex.

Research paper thumbnail of Genetic subtyping of Fanconi anemia by comprehensive mutation screening

Human Mutation, 2008

Communicated by Christopher G. Mathew Fanconi anemia (FA) is a recessively inherited syndrome wit... more Communicated by Christopher G. Mathew Fanconi anemia (FA) is a recessively inherited syndrome with predisposition to bone marrow failure and malignancies. Hypersensitivity to cross-linking agents is a cellular feature used to confirm the diagnosis. The mode of inheritance is autosomal recessive (12 subtypes) as well as X-linked (one subtype). Most genetic subtypes have initially been defined as ''complementation groups'' by cell fusion studies. Here we report a comprehensive genetic subtyping approach for FA that is primarily based on mutation screening, supplemented by protein expression analysis and by functional assays to test for pathogenicity of unclassified variants. Of 80 FA cases analyzed, 73 (91%) were successfully subtyped. In total, 92 distinct mutations were detected, of which 56 were novel (40 in FANCA, eight in FANCC, two in FANCD1, three in FANCE, one in FANCF, and three in FANCG). All known complementation groups were represented, except D2, J, L, and M. Three patients could not be classified because proliferating cell cultures from the probands were lacking. In cell lines from the remaining four patients, immunoblotting was used to determine their capacity to monoubiquitinate FANCD2. In one case FANCD2 monoubiquitination was normal, indicating a defect downstream. In the remaining three cases monoubiquitination was not detectable, indicating a defect upstream. In the latter four patients, pathogenic mutations in a known FA gene may have been missed, or these patients might represent novel genetic subtypes. We conclude that direct mutation screening allows a molecular diagnosis of FA in the vast majority of patients, even in cases where growing cells from affected individuals are unavailable. Proliferating cell lines are required in a minority (o15%) of the patients, to allow testing for FANCD2 ubiquitination status and sequencing of FANCD2 using cDNA, to avoid interference from pseudogenes.

Research paper thumbnail of Isolation of a cDNA Representing the Fanconi Anemia Complementation Group E Gene

The American Journal of Human Genetics, 2000

Research paper thumbnail of The nuclear accumulation of the Fanconi anemia protein FANCE depends on FANCC

DNA Repair, 2006

The Fanconi anemia (FA) protein FANCE is an essential component of the nuclear FA core complex, w... more The Fanconi anemia (FA) protein FANCE is an essential component of the nuclear FA core complex, which is required for monoubiquitination of the downstream target FANCD2, an important step in the FA pathway of DNA cross-link repair. FANCE is predominantly localized in the nucleus and acts as a molecular bridge between the FA core complex and FANCD2, through direct binding of both FANCC and FANCD2. At present, it is poorly understood how the nuclear accumulation of FANCE is regulated and therefore we investigated the nuclear localization of this FA protein. We found that FANCE has a strong tendency to localize in the nucleus, since the addition of a nuclear export signal does not interfere with the nuclear localization of FANCE. We also demonstrate that the nuclear accumulation of FANCE does not rely solely on its nuclear localization signal motifs, but also on FANCC. The other FA proteins are not involved in the nuclear accumulation of FANCE, indicating a tight relationship between FANCC and FANCE, as suggested from their direct interaction. Finally, we show that the region of FANCE interacting with FANCC appears to be different from the region involved in binding FANCD2. This strengthens the idea that FANCE recruits FANCD2 to the core complex, without interfering with the binding of FANCC.

Research paper thumbnail of The nuclear accumulation of the Fanconi anemia protein FANCE depends on FANCC

Research paper thumbnail of Estimating the effect-size of gene dosage on cognitive ability across the coding genome

Rare genomic Copy Number Variants (CNVs) are major contributors to neurodevelopmental disorder. T... more Rare genomic Copy Number Variants (CNVs) are major contributors to neurodevelopmental disorder. The vast majority of pathogenic CNVs reported back to patients are ultra-rare and their quantitative effects on traits such as intelligence are undocumented. Here, we identified all CNVs ≥ 50 kilobase in 24,092 individuals from unselected and autism cohorts. We developed statistical models to estimate the effect-size of CNVs on intelligence based on their coding and non-coding characteristics. Measures of intolerance to haploinsufficiency best explained the effect of any deletion or duplication on general intelligence. There was no heterogeneity across unselected and autism cohorts. Validation was performed using an intraclass concordance and showed that model estimates of general intelligence were 78% accurate with mean effect-sizes previously published for 47 CNVs. Inheritance data on 27,766 CNVs showed that deletions and duplications with the same large effect-size on intelligence occur de novo at the same frequency. Our first outline for the effect sizes of all coding genes on intelligence suggests that around 10,000 genes affect this trait.

Research paper thumbnail of NUP98-BPTF gene fusion identified in primary refractory acute megakaryoblastic leukemia of infancy

Genes, chromosomes & cancer, Jun 1, 2018

The advent of large scale genomic sequencing technologies significantly improved the molecular cl... more The advent of large scale genomic sequencing technologies significantly improved the molecular classification of acute megakaryoblastic leukaemia (AMKL). AMKL represents a subset (∼10%) of high fatality pediatric acute myeloid leukemia (AML). Recurrent and mutually exclusive chimeric gene fusions associated with pediatric AMKL are found in 60%-70% of cases and include RBM15-MKL1, CBFA2T3-GLIS2, NUP98-KDM5A and MLL rearrangements. In addition, another 4% of AMKL harbor NUP98 rearrangements (NUP98r), with yet undetermined fusion partners. We report a novel NUP98-BPTF fusion in an infant presenting with primary refractory AMKL. In this NUP98r, the C-terminal chromatin recognition modules of BPTF, a core subunit of the NURF (nucleosome remodeling factor) ATP-dependent chromatin-remodeling complex, are fused to the N-terminal moiety of NUP98, creating an in frame NUP98-BPTF fusion, with structural homology to NUP98-KDM5A. The leukemic blasts expressed two NUP98-BPTF splicing variants, co...

Research paper thumbnail of The Fanconi Anemia Gene Product FANCF Is a Flexible Adaptor Protein

Journal of Biological Chemistry, 2004

The Fanconi anemia (FA) protein FANCF is an essential component of a nuclear core complex that pr... more The Fanconi anemia (FA) protein FANCF is an essential component of a nuclear core complex that protects the genome against chromosomal instability, but the specific function of FANCF is still poorly understood. Based upon the homology between human and Xenopus laevis FANCF, we carried out an extensive mutagenesis study to examine which domains are functionally important and to gain more insight into the function of FANCF. In contrast to previous suggestions, we show that FANCF does not have a ROM-like function. We found that the C terminus of FANCF interacts directly with FANCG and allows the assembly of other FA proteins into a stable complex. The N terminus appears to stabilize the interaction with FANCA and FANCG and is essential for the binding of the FANCC/FANCE subcomplex. We identified several important amino acids in this N-terminal region but, surprisingly, many amino acid changes failed to affect the function of the FANCF protein. Our data demonstrate that FANCF acts as a flexible adaptor protein that plays a key role in the proper assembly of the FA core complex.

Research paper thumbnail of Genetic subtyping of Fanconi anemia by comprehensive mutation screening

Human Mutation, 2008

Communicated by Christopher G. Mathew Fanconi anemia (FA) is a recessively inherited syndrome wit... more Communicated by Christopher G. Mathew Fanconi anemia (FA) is a recessively inherited syndrome with predisposition to bone marrow failure and malignancies. Hypersensitivity to cross-linking agents is a cellular feature used to confirm the diagnosis. The mode of inheritance is autosomal recessive (12 subtypes) as well as X-linked (one subtype). Most genetic subtypes have initially been defined as ''complementation groups'' by cell fusion studies. Here we report a comprehensive genetic subtyping approach for FA that is primarily based on mutation screening, supplemented by protein expression analysis and by functional assays to test for pathogenicity of unclassified variants. Of 80 FA cases analyzed, 73 (91%) were successfully subtyped. In total, 92 distinct mutations were detected, of which 56 were novel (40 in FANCA, eight in FANCC, two in FANCD1, three in FANCE, one in FANCF, and three in FANCG). All known complementation groups were represented, except D2, J, L, and M. Three patients could not be classified because proliferating cell cultures from the probands were lacking. In cell lines from the remaining four patients, immunoblotting was used to determine their capacity to monoubiquitinate FANCD2. In one case FANCD2 monoubiquitination was normal, indicating a defect downstream. In the remaining three cases monoubiquitination was not detectable, indicating a defect upstream. In the latter four patients, pathogenic mutations in a known FA gene may have been missed, or these patients might represent novel genetic subtypes. We conclude that direct mutation screening allows a molecular diagnosis of FA in the vast majority of patients, even in cases where growing cells from affected individuals are unavailable. Proliferating cell lines are required in a minority (o15%) of the patients, to allow testing for FANCD2 ubiquitination status and sequencing of FANCD2 using cDNA, to avoid interference from pseudogenes.

Research paper thumbnail of Isolation of a cDNA Representing the Fanconi Anemia Complementation Group E Gene

The American Journal of Human Genetics, 2000

Research paper thumbnail of The nuclear accumulation of the Fanconi anemia protein FANCE depends on FANCC

DNA Repair, 2006

The Fanconi anemia (FA) protein FANCE is an essential component of the nuclear FA core complex, w... more The Fanconi anemia (FA) protein FANCE is an essential component of the nuclear FA core complex, which is required for monoubiquitination of the downstream target FANCD2, an important step in the FA pathway of DNA cross-link repair. FANCE is predominantly localized in the nucleus and acts as a molecular bridge between the FA core complex and FANCD2, through direct binding of both FANCC and FANCD2. At present, it is poorly understood how the nuclear accumulation of FANCE is regulated and therefore we investigated the nuclear localization of this FA protein. We found that FANCE has a strong tendency to localize in the nucleus, since the addition of a nuclear export signal does not interfere with the nuclear localization of FANCE. We also demonstrate that the nuclear accumulation of FANCE does not rely solely on its nuclear localization signal motifs, but also on FANCC. The other FA proteins are not involved in the nuclear accumulation of FANCE, indicating a tight relationship between FANCC and FANCE, as suggested from their direct interaction. Finally, we show that the region of FANCE interacting with FANCC appears to be different from the region involved in binding FANCD2. This strengthens the idea that FANCE recruits FANCD2 to the core complex, without interfering with the binding of FANCC.