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Cells Jun 2024Primary ciliary dyskinesia (PCD) is a rare, genetically heterogeneous, motile ciliopathy, characterized by neonatal respiratory distress, recurrent upper and lower... (Review)
Review
Primary ciliary dyskinesia (PCD) is a rare, genetically heterogeneous, motile ciliopathy, characterized by neonatal respiratory distress, recurrent upper and lower respiratory tract infections, subfertility, and laterality defects. Diagnosis relies on a combination of tests for confirmation, including nasal nitric oxide (nNO) measurements, high-speed videomicroscopy analysis (HSVMA), immunofluorescent staining, axonemal ultrastructure analysis via transmission electron microscopy (TEM), and genetic testing. Notably, there is no single gold standard confirmatory or exclusionary test. Currently, 54 causative genes involved in cilia assembly, structure, and function have been linked to PCD; this rare disease has a spectrum of clinical manifestations and emerging genotype-phenotype relationships. In this review, we provide an overview of the structure and function of motile cilia, the emerging genetics and pathophysiology of this rare disease, as well as clinical features associated with motile ciliopathies, novel diagnostic tools, and updates on genotype-phenotype relationships in PCD.
Topics: Humans; Cilia; Ciliary Motility Disorders; Phenotype
PubMed: 38891105
DOI: 10.3390/cells13110974 -
Frontiers in Cell and Developmental... 2024The unicellular green alga, i, has played a central role in discovering much of what is currently known about the composition, assembly, and function of cilia and... (Review)
Review
The unicellular green alga, i, has played a central role in discovering much of what is currently known about the composition, assembly, and function of cilia and flagella. combines excellent genetics, such as the ability to grow cells as haploids or diploids and to perform tetrad analysis, with an unparalleled ability to detach and isolate flagella in a single step without cell lysis. The combination of genetics and biochemistry that is possible in has allowed many of the key components of the cilium to be identified by looking for proteins that are missing in a defined mutant. Few if any other model organisms allow such a seamless combination of genetic and biochemical approaches. Other major advantages of compared to other systems include the ability to induce flagella to regenerate in a highly synchronous manner, allowing the kinetics of flagellar growth to be measured, and the ability of flagella to adhere to glass coverslips allowing Intraflagellar Transport to be easily imaged inside the flagella of living cells, with quantitative precision and single-molecule resolution. These advantages continue to work in favor of as a model system going forward, and are now augmented by extensive genomic resources, a knockout strain collection, and efficient CRISPR gene editing. While has obvious limitations for studying ciliary functions related to animal development or organ physiology, when it comes to studying the fundamental biology of cilia and flagella, is simply unmatched in terms of speed, efficiency, cost, and the variety of approaches that can be brought to bear on a question.
PubMed: 38872931
DOI: 10.3389/fcell.2024.1412641 -
Asian Journal of Andrology Jun 2024Male infertility is a worldwide health issue, affecting 8%-12% of the global population. Oligoasthenoteratozoospermia (OAT) represents a severe type of male infertility,...
Male infertility is a worldwide health issue, affecting 8%-12% of the global population. Oligoasthenoteratozoospermia (OAT) represents a severe type of male infertility, characterized by reduced sperm count and motility and an increased frequency of sperm with aberrant morphology. Using whole-exome sequencing, this study identified a novel missense mutation (c.848C>A, p.A283E) in the coiled-coil domain-containing 34 gene (CCDC34) in a consanguineous Pakistani family. This rare mutation was predicted to be deleterious and to affect the protein stability. Hematoxylin and eosin staining of spermatozoa from the patient with OAT revealed multiple morphological abnormalities of the flagella and transmission electron microscopy indicated axonemal ultrastructural defects with a lack of outer dynein arms. These findings indicated that CCDC34 plays a role in maintaining the axonemal ultrastructure and the assembly or stability of the outer dynein arms, thus expanding the phenotypic spectrum of CCDC34 missense mutations.
PubMed: 38856307
DOI: 10.4103/aja202432 -
The Journal of Cell Biology Sep 2024Two sets of motor proteins underpin motile cilia/flagella function. The axoneme-associated inner and outer dynein arms drive sliding of adjacent axoneme microtubule...
Two sets of motor proteins underpin motile cilia/flagella function. The axoneme-associated inner and outer dynein arms drive sliding of adjacent axoneme microtubule doublets to periodically bend the flagellum for beating, while intraflagellar transport (IFT) kinesins and dyneins carry IFT trains bidirectionally along the axoneme. Despite assembling motile cilia and flagella, IFT train speeds have only previously been quantified in immobilized flagella-mechanical immobilization or genetic paralysis. This has limited investigation of the interaction between IFT and flagellar beating. Here, in uniflagellate Leishmania parasites, we use high-frequency, dual-color fluorescence microscopy to visualize IFT train movement in beating flagella. We discovered that adhesion of flagella to a microscope slide is detrimental, reducing IFT train speed and increasing train stalling. In flagella free to move, IFT train speed is not strongly dependent on flagella beat type; however, permanent disruption of flagella beating by deletion of genes necessary for formation or regulation of beating showed an inverse correlation of beat frequency and IFT train speed.
Topics: Axoneme; Biological Transport; Cilia; Dyneins; Flagella; Kinesins; Leishmania; Protozoan Proteins; Microtubules
PubMed: 38829962
DOI: 10.1083/jcb.202401154 -
Nature Communications Jun 2024Differentiation of male gametocytes into flagellated fertile male gametes relies on the assembly of axoneme, a major component of male development for mosquito...
Differentiation of male gametocytes into flagellated fertile male gametes relies on the assembly of axoneme, a major component of male development for mosquito transmission of the malaria parasite. RNA-binding protein (RBP)-mediated post-transcriptional regulation of mRNA plays important roles in eukaryotic sexual development, including the development of female Plasmodium. However, the role of RBP in defining the Plasmodium male transcriptome and its function in male gametogenesis remains incompletely understood. Here, we performed genome-wide screening for gender-specific RBPs and identified an undescribed male-specific RBP gene Rbpm1 in the Plasmodium. RBPm1 is localized in the nucleus of male gametocytes. RBPm1-deficient parasites fail to assemble the axoneme for male gametogenesis and thus mosquito transmission. RBPm1 interacts with the spliceosome E complex and regulates the splicing initiation of certain introns in a group of 26 axonemal genes. RBPm1 deficiency results in intron retention and protein loss of these axonemal genes. Intron deletion restores axonemal protein expression and partially rectifies axonemal defects in RBPm1-null gametocytes. Further splicing assays in both reporter and endogenous genes exhibit stringent recognition of the axonemal introns by RBPm1. The splicing activator RBPm1 and its target introns constitute an axonemal intron splicing program in the post-transcriptional regulation essential for Plasmodium male development.
Topics: Introns; RNA Splicing; RNA-Binding Proteins; Animals; Protozoan Proteins; Male; Axoneme; Female; Gametogenesis; Spliceosomes; Plasmodium berghei; Malaria; Plasmodium
PubMed: 38824128
DOI: 10.1038/s41467-024-49002-9 -
Disease Models & Mechanisms May 2024Vertebrate photoreceptors are highly specialized retinal neurons that have cilium-derived membrane organelles called outer segments (OS), which function as platforms for...
Vertebrate photoreceptors are highly specialized retinal neurons that have cilium-derived membrane organelles called outer segments (OS), which function as platforms for phototransduction. Male germ cell-associated kinase (MAK) is a cilium-associated serine/threonine kinase, and its genetic mutation causes photoreceptor degeneration in mice and retinitis pigmentosa in humans. However, the role of MAK in photoreceptors is not fully understood. Here, we report that zebrafish mak mutants show rapid photoreceptor degeneration during embryonic development. In mak mutants, both cone and rod photoreceptors completely lack OSs and undergo apoptosis. Interestingly, zebrafish mak mutants fail to generate axonemes during photoreceptor ciliogenesis, whereas basal bodies are specified. These data suggest that MAK contributes to axoneme development in zebrafish, in contrast to mouse Mak mutants, which have elongated photoreceptor axonemes. Furthermore, the kinase activity of MAK is critical in ciliary axoneme development and photoreceptor survival. Thus, MAK is required for ciliogenesis and OS formation in zebrafish photoreceptors to ensure intracellular protein transport and photoreceptor survival.
PubMed: 38813692
DOI: 10.1242/dmm.050618 -
Journal of Cell Science Oct 2024The definitive demonstration of protein localization on primary cilia has been a challenge for cilia biologists. Primary cilia are solitary thread-like projections that...
The definitive demonstration of protein localization on primary cilia has been a challenge for cilia biologists. Primary cilia are solitary thread-like projections that have a specialized protein composition, but as the ciliary structure overlays the cell membrane and other cell parts, the identity of ciliary proteins are difficult to ascertain by conventional imaging approaches like immunofluorescence microscopy. Surface scanning electron microscopy combined with immunolabeling (immuno-SEM) bypasses some of these indeterminacies by unambiguously showing protein expression in the context of the three-dimensional ultrastructure of the cilium. Here, we apply immuno-SEM to specifically identify proteins on the primary cilia of mouse and human pancreatic islets, including post-translationally modified tubulin, intraflagellar transport (IFT)88, the small GTPase Arl13b, as well as subunits of axonemal dynein. Key parameters in sample preparation, immunolabeling and imaging acquisition are discussed to facilitate similar studies by others in the cilia research community.
Topics: Cilia; Animals; Humans; Mice; Islets of Langerhans; Microscopy, Electron, Scanning
PubMed: 38804679
DOI: 10.1242/jcs.262038 -
Journal of Physiological Investigation Mar 2024Uterine adenomyosis is an estrogen-dependent chronic inflammatory condition and may cause painful symptoms, abnormal uterine bleeding, and/or subfertility/infertility.... (Review)
Review
Uterine adenomyosis is an estrogen-dependent chronic inflammatory condition and may cause painful symptoms, abnormal uterine bleeding, and/or subfertility/infertility. It is characterized by the presence of endometrial glands and stroma within the myometrium causing enlargement of the uterus as a result of reactive hyperplastic and/or hypertrophic change of the surrounding myometrium. Similar to endometriosis, adenomyosis has a negative impact on female fertility. Abnormal uterotubal sperm transport, tissue inflammation, and the toxic effect of chemical mediators have been proposed as contributing factors. Inflammation-induced damage of the mucosal cilia in the fallopian tube has been reported. Besides other proposed mechanisms, our most recent study with transmission electron microscopy analysis indicated that microvilli damage and an axonemal alteration in the apical endometria occur in response to endometrial inflammation. This may be involved in the negative fertility outcome in women with adenomyosis. We present a critical analysis of the literature data concerning the mechanistic basis of infertility in women with adenomyosis and its impact on fertility outcome.
Topics: Humans; Female; Adenomyosis; Infertility, Female; Endometrium; Cilia
PubMed: 38780290
DOI: 10.4103/ejpi.EJPI-D-24-00032 -
EMBO Reports Jun 2024Alpha, beta, and gamma tubulins are essential building blocks for all eukaryotic cells. The functions of the non-canonical tubulins, delta, epsilon, and zeta, however,...
Alpha, beta, and gamma tubulins are essential building blocks for all eukaryotic cells. The functions of the non-canonical tubulins, delta, epsilon, and zeta, however, remain poorly understood and their requirement in mammalian development untested. Herein we have used a spermatogenesis model to define epsilon tubulin (TUBE1) function in mice. We show that TUBE1 is essential for the function of multiple complex microtubule arrays, including the meiotic spindle, axoneme and manchette and in its absence, there is a dramatic loss of germ cells and male sterility. Moreover, we provide evidence for the interplay between TUBE1 and katanin-mediated microtubule severing, and for the sub-specialization of individual katanin paralogs in the regulation of specific microtubule arrays.
Topics: Animals; Male; Microtubules; Tubulin; Mice; Katanin; Spermatogenesis; Adenosine Triphosphatases; Germ Cells; Spindle Apparatus; Spermatozoa; Infertility, Male; Mice, Knockout; Axoneme
PubMed: 38773322
DOI: 10.1038/s44319-024-00159-w -
The Journal of Biological Chemistry May 2024Motile cilia on the cell surface produce fluid flows in the body and abnormalities in motile cilia cause primary ciliary dyskinesia. Dynein axonemal assembly factor 6...
Motile cilia on the cell surface produce fluid flows in the body and abnormalities in motile cilia cause primary ciliary dyskinesia. Dynein axonemal assembly factor 6 (DNAAF6), a causative gene of primary ciliary dyskinesia, was isolated as an interacting protein with La ribonucleoprotein 6 (LARP6) that regulates ciliogenesis in multiciliated cells (MCCs). In MCCs of Xenopus embryos, LARP6 and DNAAF6 were colocalized in biomolecular condensates termed dynein axonemal particles and synergized to control ciliogenesis. Moreover, tubulin alpha 1c-like mRNA encoding α-tubulin protein, that is a major component of ciliary axoneme, was identified as a target mRNA regulated by binding LARP6. While DNAAF6 was necessary for high α-tubulin protein expression near the apical side of Xenopus MCCs during ciliogenesis, its mutant, which abolishes binding with LARP6, was unable to restore the expression of α-tubulin protein near the apical side of MCCs in Xenopus DNAAF6 morphant. These results indicated that the binding of LARP6 and DNAAF6 in dynein axonemal particles regulates highly expressed α-tubulin protein near the apical side of Xenopus MCCs during ciliogenesis.
PubMed: 38762183
DOI: 10.1016/j.jbc.2024.107373