Browsing by Author "Kubisch, Christian"

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    The analysis of heterotaxy patients reveals new loss-of-function variants of GRK5
    (SpringerNature, 2016-09-13) Lessel, Davor; Muhammad, Tariq; Tena, Teresa Casar; Moepps, Barbara; Burkhalter, Martin D.; Hitz, Marc-Phillip; Toka, Okan; Rentzsch, Axel; Schubert, Stephan; Schalinski, Adelheid; Bauer, Ulrike M. M.; Kubisch, Christian; Ware, Stephanie M.; Philipp, Melanie; Department of Pediatrics, IU School of Medicine
    G protein-coupled receptor kinase 5 (GRK5) is a regulator of cardiac performance and a potential therapeutic target in heart failure in the adult. Additionally, we have previously classified GRK5 as a determinant of left-right asymmetry and proper heart development using zebrafish. We thus aimed to identify GRK5 variants of functional significance by analysing 187 individuals with laterality defects (heterotaxy) that were associated with a congenital heart defect (CHD). Using Sanger sequencing we identified two moderately frequent variants in GRK5 with minor allele frequencies <10%, and seven very rare polymorphisms with minor allele frequencies <1%, two of which are novel variants. Given their evolutionarily conserved position in zebrafish, in-depth functional characterisation of four variants (p.Q41L, p.G298S, p.R304C and p.T425M) was performed. We tested the effects of these variants on normal subcellular localisation and the ability to desensitise receptor signalling as well as their ability to correct the left-right asymmetry defect upon Grk5l knockdown in zebrafish. While p.Q41L, p.R304C and p.T425M responded normally in the first two aspects, neither p.Q41L nor p.R304C were capable of rescuing the lateralisation phenotype. The fourth variant, p.G298S was identified as a complete loss-of-function variant in all assays and provides insight into the functions of GRK5.
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    DNA-binding affinity and specificity determine the phenotypic diversity in BCL11B-related disorders
    (Elsevier, 2025) Lessel, Ivana; Baresic, Anja; Chinn, Ivan K.; May, Jonathan; Goenka, Anu; Chandler, Kate E.; Posey, Jennifer E.; Afenjar, Alexandra; Averdunk, Luisa; Bedeschi, Maria Francesca; Besnard, Thomas; Brager, Rae; Brick, Lauren; Brugger, Melanie; Brunet, Theresa; Byrne, Susan; de la Calle-Martín, Oscar; Capra, Valeria; Cardenas, Paul; Chappé, Céline; Chong, Hey J.; Cogne, Benjamin; Conboy, Erin; Cope, Heidi; Courtin, Thomas; Deb, Wallid; Dilena, Robertino; Dubourg, Christèle; Elgizouli, Magdeldin; Fernandes, Erica; Fitzgerald, Kristi K.; Gangi, Silvana; George-Abraham, Jaya K.; Gucsavas-Calikoglu, Muge; Haack, Tobias B.; Hadonou, Medard; Hanker, Britta; Hüning, Irina; Iascone, Maria; Isidor, Bertrand; Järvelä, Irma; Jin, Jay J.; Jorge, Alexander A. L.; Josifova, Dragana; Kalinauskiene, Ruta; Kamsteeg, Erik-Jan; Keren, Boris; Kessler, Elena; Kölbel, Heike; Kozenko, Mariya; Kubisch, Christian; Kuechler, Alma; Leal, Suzanne M.; Leppälä, Juha; Luu, Sharon M.; Lyon, Gholson J.; Madan-Khetarpal, Suneeta; Mancardi, Margherita; Marchi, Elaine; Mehta, Lakshmi; Menendez, Beatriz; Morel, Chantal F.; Moyer Harasink, Sue; Nevay, Dayna-Lynn; Nigro, Vincenzo; Odent, Sylvie; Oegema, Renske; Pappas, John; Pastore, Matthew T.; Perilla-Young, Yezmin; Platzer, Konrad; Powell-Hamilton, Nina; Rabin, Rachel; Rekab, Aisha; Rezende, Raissa C.; Robert, Leema; Romano, Ferruccio; Scala, Marcello; Poths, Karin; Schrauwen, Isabelle; Sebastian, Jessica; Short, John; Sidlow, Richard; Sullivan, Jennifer; Szakszon, Katalin; Tan, Queenie K. G.; Undiagnosed Diseases Network; Wagner, Matias; Wieczorek, Dagmar; Yuan, Bo; Maeding, Nicole; Strunk, Dirk; Begtrup, Amber; Banka, Siddharth; Lupski, James R.; Tolosa, Eva; Lessel, Davor; Medical and Molecular Genetics, School of Medicine
    BCL11B is a Cys2-His2 zinc-finger (C2H2-ZnF) domain-containing, DNA-binding, transcription factor with established roles in the development of various organs and tissues, primarily the immune and nervous systems. BCL11B germline variants have been associated with a variety of developmental syndromes. However, genotype-phenotype correlations along with pathophysiologic mechanisms of selected variants mostly remain elusive. To dissect these, we performed genotype-phenotype correlations of 92 affected individuals harboring a pathogenic or likely pathogenic BCL11B variant, followed by immune phenotyping, analysis of chromatin immunoprecipitation DNA-sequencing data, dual-luciferase reporter assays, and molecular modeling. These integrative analyses enabled us to define three clinical subtypes of BCL11B-related disorders. It is likely that gene-disruptive BCL11B variants and missense variants affecting zinc-binding cysteine and histidine residues cause mild to moderate neurodevelopmental delay with increased propensity for behavioral and dental anomalies, allergies and asthma, and reduced type 2 innate lymphoid cells. Missense variants within C2H2-ZnF DNA-contacting α helices cause highly variable clinical presentations ranging from multisystem anomalies with demise in the first years of life to late-onset, hyperkinetic movement disorder with poor fine motor skills. Those not in direct DNA contact cause a milder phenotype through reduced, target-specific transcriptional activity. However, missense variants affecting C2H2-ZnFs, DNA binding, and "specificity residues" impair BCL11B transcriptional activity in a target-specific, dominant-negative manner along with aberrant regulation of alternative DNA targets, resulting in more severe and unpredictable clinical outcomes. Taken together, we suggest that the phenotypic severity and variability is largely dependent on the DNA-binding affinity and specificity of altered BCL11B proteins.