scholarly journals SOX10 Mutation Screening for 117 Patients with Kallmann Syndrome

2021 ◽  
Author(s):  
Hirohito Shima ◽  
Etsuro Tokuhiro ◽  
Shingo Okamoto ◽  
Mariko Nagamori ◽  
Tsutomu Ogata ◽  
...  
Keyword(s):  
Hypogonadotropic Hypogonadism ◽  
Mutation Screening ◽  
Hirschsprung Disease ◽  
Kallmann Syndrome ◽  
Dominant Negative ◽  
Negative Effects ◽  
Causative Gene ◽  
Pathogenic Variants ◽  
Medical Genomics

Abstract Introduction Kallmann syndrome (KS) is a genetically heterogeneous condition characterized by hypogonadotropic hypogonadism (HH) and olfactory dysfunction. Although SOX10, a causative gene for Waardenburg syndrome (WS) and peripheral demyelinating neuropathy, central demyelination, WS, and Hirschsprung disease (PCWH), has previously been implicated in KS, the clinical significance of SOX10 variants as the cause of KS remains uncertain. Patients and Methods A total of 117 patients with KS underwent mutation screening of SOX10 and 14 other causative genes for KS/HH. Rare SOX10 variants were subjected to in silico and in vitro analyses. We also examined clinical data of the patients and their parents with SOX10 variants. Results Sequence analysis identified two heterozygous variants of SOX10 (c.1225G>T, p.Gly409* and c.475C>T, p.Arg159Trp) in patients 1–3, as well as in the parents of patients 1 and 3. The variants were assessed as pathogenic/likely_pathogenic, according to the American College of Medical Genomics guidelines. Both variants lacked in vitro transactivating activity for the MITF promoter and exerted no dominant-negative effects. Patients 1–3 carried no pathogenic variants in other genes examined. The patients presented with typical KS, while such features were absent in the parents of patients 1 and 3. None of the five variant-positive individuals exhibited hypopigmentation, while one and two individuals exhibited complete and partial hearing loss, respectively. Conclusion These results provide evidence that SOX10 haploinsufficiency accounts for a few percent of KS cases. SOX10 haploinsufficiency is likely to be associated with a broad phenotypic spectrum which includes KS without other clinical features of WS/PCWH.

scholarly journals Dominant Negative Mutants Implicate STAT5 in Myeloid Cell Proliferation and Neutrophil Differentiation

Blood ◽  
1999 ◽  
Vol 93 (12) ◽  
pp. 4154-4166 ◽  
Author(s):  
Robert L. Ilaria ◽  
Robert G. Hawley ◽  
Richard A. Van Etten
Keyword(s):  
Dna Binding ◽  
Transcriptional Activation ◽  
Dominant Negative ◽  
Dominant Negative Effect ◽  
Cytokine Signaling ◽  
Transactivation Domain ◽  
Negative Effects ◽  
Murine Bone Marrow ◽  
Negative Effect

Abstract STAT5 is a member of the signal transducers and activation of transcription (STAT) family of latent transcription factors activated in a variety of cytokine signaling pathways. We introduced alanine substitution mutations in highly conserved regions of murine STAT5A and studied the mutants for dimerization, DNA binding, transactivation, and dominant negative effects on erythropoietin-induced STAT5-dependent transcriptional activation. The mutations included two near the amino-terminus (W255KR→AAA and R290QQ→AAA), two in the DNA-binding domain (E437E→AA and V466VV→AAA), and a carboxy-terminal truncation of STAT5A (STAT5A/▵53C) analogous to a naturally occurring isoform of rat STAT5B. All of the STAT mutant proteins were tyrosine phosphorylated by JAK2 and heterodimerized with STAT5B except for the WKR mutant, suggesting an important role for this region in STAT5 for stabilizing dimerization. The WKR, EE, and VVV mutants had no detectable DNA-binding activity, and the WKR and VVV mutants, but not EE, were defective in transcriptional induction. The VVV mutant had a moderate dominant negative effect on erythropoietin-induced STAT5 transcriptional activation, which was likely due to the formation of heterodimers that are defective in DNA binding. Interestingly, the WKR mutant had a potent dominant negative effect, comparable to the transactivation domain deletion mutant, ▵53C. Stable expression of either the WKR or ▵53C STAT5 mutants in the murine myeloid cytokine-dependent cell line 32D inhibited both interleukin-3–dependent proliferation and granulocyte colony-stimulating factor (G-CSF)–dependent differentiation, without induction of apoptosis. Expression of these mutants in primary murine bone marrow inhibited G-CSF–dependent granulocyte colony formation in vitro. These results demonstrate that mutations in distinct regions of STAT5 exert dominant negative effects on cytokine signaling, likely through different mechanisms, and suggest a role for STAT5 in proliferation and differentiation of myeloid cells.

scholarly journals The human SKA complex drives the metaphase-anaphase cell cycle transition by recruiting protein phosphatase 1 to kinetochores

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Sushama Sivakumar ◽  
Paweł Ł Janczyk ◽  
Qianhui Qu ◽  
Chad A Brautigam ◽  
P Todd Stukenberg ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Force Production ◽  
Dominant Negative ◽  
Protein Phosphatase 1 ◽  
Negative Effects ◽  
Checkpoint Signaling ◽  
Anaphase Onset ◽  
Spindle Microtubules ◽  
Cell Cycle Transition

The spindle- and kinetochore-associated (Ska) complex is essential for normal anaphase onset in mitosis. The C-terminal domain (CTD) of Ska1 binds microtubules and was proposed to facilitate kinetochore movement on depolymerizing spindle microtubules. Here, we show that Ska complex recruits protein phosphatase 1 (PP1) to kinetochores. This recruitment requires the Ska1 CTD, which binds PP1 in vitro and in human HeLa cells. Ska1 lacking its CTD fused to a PP1-binding peptide or fused directly to PP1 rescues mitotic defects caused by Ska1 depletion. Ska1 fusion to catalytically dead PP1 mutant does not rescue and shows dominant negative effects. Thus, the Ska complex, specifically the Ska1 CTD, recruits PP1 to kinetochores to oppose spindle checkpoint signaling kinases and promote anaphase onset. Microtubule binding by Ska, rather than acting in force production for chromosome movement, may instead serve to promote PP1 recruitment to kinetochores fully attached to spindle microtubules at metaphase.

scholarly journals Dominant Negative Mutants Implicate STAT5 in Myeloid Cell Proliferation and Neutrophil Differentiation

Blood ◽  
1999 ◽  
Vol 93 (12) ◽  
pp. 4154-4166 ◽  
Author(s):  
Robert L. Ilaria ◽  
Robert G. Hawley ◽  
Richard A. Van Etten
Keyword(s):  
Dna Binding ◽  
Transcriptional Activation ◽  
Dominant Negative ◽  
Dominant Negative Effect ◽  
Cytokine Signaling ◽  
Transactivation Domain ◽  
Negative Effects ◽  
Murine Bone Marrow ◽  
Negative Effect

STAT5 is a member of the signal transducers and activation of transcription (STAT) family of latent transcription factors activated in a variety of cytokine signaling pathways. We introduced alanine substitution mutations in highly conserved regions of murine STAT5A and studied the mutants for dimerization, DNA binding, transactivation, and dominant negative effects on erythropoietin-induced STAT5-dependent transcriptional activation. The mutations included two near the amino-terminus (W255KR→AAA and R290QQ→AAA), two in the DNA-binding domain (E437E→AA and V466VV→AAA), and a carboxy-terminal truncation of STAT5A (STAT5A/▵53C) analogous to a naturally occurring isoform of rat STAT5B. All of the STAT mutant proteins were tyrosine phosphorylated by JAK2 and heterodimerized with STAT5B except for the WKR mutant, suggesting an important role for this region in STAT5 for stabilizing dimerization. The WKR, EE, and VVV mutants had no detectable DNA-binding activity, and the WKR and VVV mutants, but not EE, were defective in transcriptional induction. The VVV mutant had a moderate dominant negative effect on erythropoietin-induced STAT5 transcriptional activation, which was likely due to the formation of heterodimers that are defective in DNA binding. Interestingly, the WKR mutant had a potent dominant negative effect, comparable to the transactivation domain deletion mutant, ▵53C. Stable expression of either the WKR or ▵53C STAT5 mutants in the murine myeloid cytokine-dependent cell line 32D inhibited both interleukin-3–dependent proliferation and granulocyte colony-stimulating factor (G-CSF)–dependent differentiation, without induction of apoptosis. Expression of these mutants in primary murine bone marrow inhibited G-CSF–dependent granulocyte colony formation in vitro. These results demonstrate that mutations in distinct regions of STAT5 exert dominant negative effects on cytokine signaling, likely through different mechanisms, and suggest a role for STAT5 in proliferation and differentiation of myeloid cells.

scholarly journals A novel SOX10 variant in a Japanese girl with Waardenburg syndrome type 4C and Kallmann syndrome

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Junpei Hamada ◽  
Fumihiro Ochi ◽  
Yuka Sei ◽  
Koji Takemoto ◽  
Hiroki Hirai ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Hypogonadotropic Hypogonadism ◽  
Hirschsprung Disease ◽  
Kallmann Syndrome ◽  
Syndrome Type ◽  
Waardenburg Syndrome ◽  
First Case ◽  
Iris Depigmentation ◽  
Bilateral Sensorineural Hearing Loss

AbstractWe report the first case of Waardenburg syndrome type 4C and Kallmann syndrome in the same person. The patient, a Japanese girl, presented with bilateral iris depigmentation, bilateral sensorineural hearing loss, Hirschsprung disease, hypogonadotropic hypogonadism, and anosmia. We identified a novel SOX10 variant, c.124delC, p.Leu42Cysfs*67.

scholarly journals Parallel Multi-Gene Panel Testing for Diagnosis of Idiopathic Hypogonadotropic Hypogonadism/Kallmann Syndrome

2019 ◽  
Vol 2019 ◽  
pp. 1-3 ◽  
Author(s):  
Manickavasagam Senthilraja ◽  
Aaron Chapla ◽  
Felix K. Jebasingh ◽  
Dukhabhandhu Naik ◽  
Thomas V. Paul ◽  
...  
Keyword(s):  
Gene Mutation ◽  
Hypogonadotropic Hypogonadism ◽  
Cost Effective ◽  
Kallmann Syndrome ◽  
Causative Gene ◽  
Idiopathic Hypogonadotropic Hypogonadism ◽  
Panel Testing ◽  
Kal1 Gene ◽  
Gene Panel Testing ◽  
The Subject

Kallmann syndrome (KS)/Idiopathic hypogonadotropic hypogonadism (IHH) is characterized by hypogonadotropic hypogonadism and anosmia or hyposmia due to the abnormal migration of olfactory and gonadotropin releasing hormone producing neurons. Multiple genes have been implicated in KS/IHH. Sequential testing of these genes utilising Sanger sequencing is time consuming and not cost effective. The introduction of parallel multigene panel sequencing of small gene panels for the identification of causative gene variants has been shown to be a robust tool in the clinical setting. Utilizing multiplex PCR for the four gene KS/IHH panel followed by NGS, we describe herewith two cases of hypogonadotropic hypogonadism with a Prokineticin receptor 2 (PROKR2) gene and KAL1 gene mutation. The subject with a PROKR2 mutation had a normal perception of smell and normal olfactory bulbs on imaging. The subject with a KAL1 gene mutation had anosmia and a hypoplastic olfactory bulb.

scholarly journals Congenital hypothalamic hypogonadism — a Kallmann syndrome in boys. Clinical cases

2021 ◽  
pp. 53-65
Author(s):  
E. V. Globa ◽  
N. B. Zelinska ◽  
V. A. Yengovatova ◽  
O. A. Horosha ◽  
N. L. Pogadayeva ◽  
...  
Keyword(s):  
Genetic Testing ◽  
Wide Spectrum ◽  
Hypogonadotropic Hypogonadism ◽  
Genetic Diagnosis ◽  
Previous Treatment ◽  
Kallmann Syndrome ◽  
Positive Trend ◽  
Targeted Next Generation Sequencing ◽  
Pathogenic Variants ◽  
Different Response

Central hypogonadism (CH) is a rare disease that occurs with a frequency of 1 : 8000 in women and 1 : 4000 in men. In 60 % of cases of CH, it is caused by Kallmann syndrome (KS) — a disease in which hypogonadotropic hypogonadism is combined with olfactory disorders (hyposmia or anosmia).Aim — to study clinical features, principles of diagnosis of CH/KS and evaluation of the effectiveness of various treatment. Materials and methods. 4 cases with CH/KS from three families had been described. Laboratory and instrumental investigations were used to confirm the KS; genetic diagnosis was performed using targeted next-generation sequencing (tNGS hypogonadotropic panel).Results. Patients with CH/KS had a wide spectrum of genital disorders (micropenia, cryptorchidism, microorchidism), which appeared at different age. Extragenital pathology was found in three of four patients: namely disorders of kidney, eye, respiratory system, hypoparathyroidism, hypothyroidism and epilepsy. It should be noted that all patients had olfactory disorders, which appeared in two of them only during a detailed survey after receiving genetic testing. In all patients, the diagnosis of CH was confirmed by the test with triptorelin 0.1. Also, all patients who underwent densitometry were found to have significant osteoporosis. In three patients, genetic testing confirmed hemizygous pathogenic variants in ANOS1 gene, while in one patient a heterozygous variant in FGFR1 gene was confirmed. After treatment with chorionic gonadotropin (HCG), two patients responded positively, with a descent of the testicles into the scrotum and an increase of testosterone level and testicular volume. However, in the other two patients there was no positive trend in treatment with HCG, therefore, the use of recombinant human FSH (r-FSH) in the form of priming and then further — in combination with HCG may be considered. Although the presence of severe microorchidism, cryptorchidism, low levels of AMH, inhibin B, and an unsatisfactory response to the previous treatment with HCG indicates extremely unfavorable prognosis. Therefore, in order to achieve the fertility in some patients with CH/KS, the most likely attempt is the use of assisted reproductive technologies.Conclusions. The leading problem in the treatment of patients with KS is their different response to hormone therapy, including different manifestations of the disease.

scholarly journals RAN/TC4 mutants identify a common requirement for snRNP and protein import into the nucleus.

1996 ◽  
Vol 133 (3) ◽  
pp. 485-494 ◽  
Author(s):  
I Palacios ◽  
K Weis ◽  
C Klebe ◽  
I W Mattaj ◽  
C Dingwall
Keyword(s):  
Nuclear Import ◽  
Protein Import ◽  
Energy Requirement ◽  
Dominant Negative ◽  
Negative Effects ◽  
Gtp Hydrolysis ◽  
Ran Gtpase ◽  
Common Component ◽  
Import Share

Kinetic competition experiments have demonstrated that at least some factors required for the nuclear import of proteins and U snRNPs are distinct. Both import processes require energy, and in the case of protein import, the energy requirement is known to be at least partly met by GTP hydrolysis by the Ran GTPase. We have compared the effects of nonhydrolyzable GTP analogues and two mutant Ran proteins on the nuclear import of proteins and U snRNPs in vitro. The mutant Ran proteins have different defects; Q69L (glutamine 69 changed to leucine) is defective in GTP hydrolysis while T24N (threonine 24 changed to asparagine) is defective in binding GTP. Both protein and snRNP import are sensitive either to the presence of the two mutant Ran proteins, which act as dominant negative inhibitors of nuclear import, or to incubation with nonhydrolyzable GTP analogues. This demonstrates that there is a requirement for a GTPase activity for the import of U snRNPs, as well as proteins, into the nucleus. The dominant negative effects of the two mutant Ran proteins indicate that the pathways of protein and snRNP import share at lease one common component.

scholarly journals In Vitro Coexpression and Pharmacological Rescue of Mutant Gonadotropin-Releasing Hormone Receptors Causing Hypogonadotropic Hypogonadism in Humans Expressing Compound Heterozygous Alleles

2005 ◽  
Vol 90 (5) ◽  
pp. 3001-3008 ◽  
Author(s):  
Alfredo Leaños-Miranda ◽  
Alfredo Ulloa-Aguirre ◽  
Jo Ann Janovick ◽  
P. Michael Conn
Keyword(s):  
Hormone Receptors ◽  
Hypogonadotropic Hypogonadism ◽  
Dominant Negative ◽  
Dominant Negative Effect ◽  
Compound Heterozygous ◽  
Receptor Function ◽  
Pharmacological Chaperones ◽  
Negative Effect ◽  
Potential Interactions

We analyzed the function of mutant GnRH receptor (GnRHR) pairs associated with compound heterozygous patients showing complete or partial forms of hypogonadotropic hypogonadism. We did this to examine potential interactions between misfolded mutants that may influence net receptor function and response to pharmacological rescue. Nine pairs of GnRHR mutants and an unreported combination (L314X(stop)/R262Q) were studied. Coexpression of each pair of mutants in COS-7 cells resulted in an active predominant effect (Q106R/L266R, A171T/Q106R, T32I/C200Y, and R262Q/A129D mutant GnRHR pairs), an additive effect (R262Q/Q106R, N10K/Q106R, and R262Q/Y284C human GnRHR pairs), or a dominant-negative effect (L314X(stop)/Q106R, Q106R+S217R/R262Q, and L314X(stop)/R262Q GnRHRs). For all combinations, addition of the pharmacoperone IN3 increased both agonist binding and effector coupling. The IN3 response was unpredictable because responses could be either similar, higher, or lower, compared with that exhibited by the less affected mutant. The clinical phenotype in patients expressing complex heterozygous alleles appears to be dictated by both the contribution from each mutant and a dominant-negative effect similar to that reported for mutants and wild-type receptor. Depending on the genotype, partial or full restoration of receptor function in response to pharmacological chaperones may be achievable goals in patients bearing inactivating mutations in the GnRHR gene.

scholarly journals Yeast Los1p Has Properties of an Exportin-Like Nucleocytoplasmic Transport Factor for tRNA

1998 ◽  
Vol 18 (11) ◽  
pp. 6374-6386 ◽  
Author(s):  
Klaus Hellmuth ◽  
Denise M. Lau ◽  
F. Ralf Bischoff ◽  
Markus Künzler ◽  
Ed Hurt ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Sequence Similarity ◽  
Nucleocytoplasmic Transport ◽  
Dominant Negative ◽  
Nuclear Pore ◽  
Negative Effects ◽  
Nuclear Pore Protein ◽  
Vitro Binding ◽  
The Family

ABSTRACT Saccharomyces cerevisiae Los1p, which is genetically linked to the nuclear pore protein Nsp1p and several tRNA biogenesis factors, was recently grouped into the family of importin/karyopherin-β-like proteins on the basis of its sequence similarity. In a two-hybrid screen, we identified Nup2p as a nucleoporin interacting with Los1p. Subsequent purification of Los1p from yeast demonstrates its physical association not only with Nup2p but also with Nsp1p. By the use of the Gsp1p-G21V mutant, Los1p was shown to preferentially bind to the GTP-bound form of yeast Ran. Furthermore, overexpression of full-length or N-terminally truncated Los1p was shown to have dominant-negative effects on cell growth and different nuclear export pathways. Finally, Los1p could interact with Gsp1p-GTP, but only in the presence of tRNA, as revealed in an indirect in vitro binding assay. These data confirm the homology between Los1p and the recently identified human exportin for tRNA and reinforce the possibility of a role for Los1p in nuclear export of tRNA in yeast.

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