Affinage

DNAH9

Dynein axonemal heavy chain 9 · UniProt Q9NYC9

Length
4486 aa
Mass
511.9 kDa
Annotated
2026-06-09
14 papers in source corpus 8 papers cited in narrative 8 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 5/5 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

DNAH9 is an axonemal beta heavy chain dynein that powers ciliary and flagellar beating, encoding a 4486-residue protein with an N-terminal stem and a C-terminal globular motor domain bearing four P-loops whose ATPase activity drives the conformational changes underlying axonemal bending (PMID:11247663). Within motile cilia DNAH9 marks a distinct outer dynein arm (ODA) subtype: together with its partner heavy chain DNAH5 it occupies type 2 ODAs restricted to the distal ciliary axoneme, and biallelic loss removes these distal ODAs, lowering beat frequency and disrupting motility of the distal cilium (PMID:15750039, PMID:30471717). DNAH9 physically associates with the ODA-related proteins CCDC114 and GAS8 and is required to maintain their protein levels, linking it to ODA docking and stability (PMID:35729109). The same dependency operates in sperm flagella, where DNAH9 is expressed in the tail and its loss causes ODA defects with reduced levels of co-assembled components DNAI1, DNAH1 and DNAH10, producing severe asthenozoospermia (PMID:33610189, PMID:39523437). In vivo, DNAH9 loss disturbs cardiac left-right patterning and compromises cardiac function (PMID:35050399).

Mechanistic history

Synthesis pass · year-by-year structured walk · 8 steps
  1. 2001 Medium

    Establishing the molecular identity of DNAH9 was the prerequisite for any functional study; cloning defined it as a full-length axonemal beta heavy chain dynein with a defined motor architecture.

    Evidence cDNA cloning, RACE, and protein domain analysis revealing four P-loops and homology to sea urchin axonemal beta heavy chains

    PMID:11247663

    Open questions at the time
    • ATPase activity inferred from domain homology, not directly measured
    • no structural model of the motor domain
  2. 2005 Medium

    It was unknown whether all ciliary ODAs were equivalent; differential axonemal distribution of DNAH9 versus DNAH5 revealed that at least two distinct ODA subtypes exist.

    Evidence High-resolution immunofluorescence of DNAH5 and DNAH9 in human respiratory epithelial and sperm cells

    PMID:15750039

    Open questions at the time
    • molecular basis of regional targeting unresolved
    • functional difference between ODA subtypes not yet tested
  3. 2018 High

    The functional role of the distal ODA subtype was undefined; loss-of-function in patients pinned DNAH9/DNAH5 type 2 ODAs to distal-cilium motility and beat frequency.

    Evidence Immunofluorescence, 3D electron tomography, high-speed video microscopy in patients plus Paramecium knockdown

    PMID:30471717

    Open questions at the time
    • does not resolve how the type 2 ODA is targeted distally
    • mechanism coupling distal ODA loss to the subtle beat defect not detailed
  4. 2021 Medium

    Whether DNAH9 acted in sperm as in respiratory cilia was unclear; patient analysis showed it is required for flagellar ODA integrity and motility, causing asthenozoospermia without respiratory disease.

    Evidence Whole exome sequencing, TEM of sperm ultrastructure, qRT-PCR and immunofluorescence of patient sperm

    PMID:33610189

    Open questions at the time
    • tissue-specific phenotype (sperm vs airway) mechanism not explained
    • single lab
  5. 2022 Medium

    The basis of DNAH9's role in ODA architecture was unknown; co-IP and knockdown defined direct partners CCDC114 and GAS8 and showed DNAH9 is needed to stabilize them.

    Evidence Co-immunoprecipitation, immunostaining and western blot in Dnah9 knockdown mice

    PMID:35729109

    Open questions at the time
    • direct versus indirect binding not distinguished
    • stoichiometry and assembly order within the ODA undefined
  6. 2022 Medium

    The organismal consequence of DNAH9 loss was untested; model-organism knockouts established a requirement in left-right patterning and cardiac function distinct from ciliogenesis itself.

    Evidence dnah9 morpholino knockdown in zebrafish and Dnah9 knockout mouse with cardiac assessment

    PMID:35050399

    Open questions at the time
    • ciliogenesis in Kupffer's vesicle unaffected, so the motility defect driving laterality is not localized
    • cardiac phenotype mechanism not dissected
  7. 2024 Medium

    Whether DNAH9 loss propagates to other ODA subunits was open; reduced DNAI1, DNAH1 and DNAH10 in patient sperm showed DNAH9 is required for assembly/stability of the broader ODA complex in flagella.

    Evidence TEM of sperm axoneme and immunofluorescence of multiple ODA components in patients

    PMID:39523437

    Open questions at the time
    • direct interaction with the reduced components not demonstrated
    • assembly hierarchy not established
  8. 2025 Low

    A specific splice variant's pathogenicity was uncharacterized; minigene analysis confirmed that correct DNAH9 pre-mRNA splicing is required for functional protein.

    Evidence Minigene splicing assay and in silico prediction in a single case report

    PMID:40376972

    Open questions at the time
    • no functional protein rescue experiment
    • single case report

Open questions

Synthesis pass · forward-looking unresolved questions
  • How DNAH9-containing type 2 ODAs are specifically targeted to the distal axoneme, and the structural basis of its motor activity, remain unresolved.
  • no structure of the DNAH9 motor domain
  • distal-targeting mechanism unknown
  • direct ATPase/motility reconstitution not reported

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0003774 cytoskeletal motor activity 2 GO:0140657 ATP-dependent activity 1
Localization
GO:0005929 cilium 3 GO:0005856 cytoskeleton 2
Pathway
R-HSA-1474165 Reproduction 2 R-HSA-1852241 Organelle biogenesis and maintenance 2
Partners
CCDC114DNAH5GAS8
Complex memberships
outer dynein arm

Evidence

Reading pass · 8 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2005 DNAH5 and DNAH9 show distinct regional distribution along the ciliary axoneme in normal human respiratory epithelial cells, indicating the existence of at least two distinct outer dynein arm (ODA) types. DNAH5 localizes along the full axoneme while DNAH9 has a different regional distribution, suggesting they form part of different ODA subtypes. High-resolution immunofluorescence imaging with specific antibodies in human respiratory epithelial and sperm cells American journal of respiratory and critical care medicine Medium 15750039
2001 DNAH9 encodes a 4486 amino acid axonemal beta heavy chain dynein consisting of an N-terminal stem and a globular C-terminus containing four P-loops that constitute the motor domain, with ATPase activity coupled to conformational changes driving cilia and flagella bending. cDNA cloning, RT-PCR, 5' RACE, cDNA library screening, genomic sequencing; protein domain analysis showing homology to sea urchin axonemal beta heavy chain dyneins (67% identity) Genomics Medium 11247663
2018 DNAH9 and its partner heavy chain DNAH5 co-localize to type 2 ODAs of the distal cilium. Loss of DNAH9 (due to biallelic mutations) causes loss of DNAH9/DNAH5-containing type 2 ODAs restricted to the distal cilia region, conferring reduced beating frequency with a subtle beating pattern defect affecting the motility of the distal cilia portion. Immunofluorescence localization, 3D electron tomography ultrastructural studies, high-speed video microscopy, next-generation sequencing; Paramecium DNAH9 knockdown as functional confirmation American journal of human genetics High 30471717
2022 DNAH9 interacts with CCDC114 and GAS8 (as shown by co-immunoprecipitation), and loss of DNAH9 (knockdown in mice) diminishes the protein levels of CCDC114 and GAS8. Co-immunoprecipitation, immunostaining, western blot in Dnah9 knockdown mice Cell death & disease Medium 35729109
2022 Dnah9 knockout in zebrafish disturbs cardiac left-right patterning without affecting ciliogenesis in Kupffer's vesicle, and Dnah9 loss in a knockout mouse model leads to compromised cardiac function. dnah9 morpholino knockdown in zebrafish; Dnah9 knockout C57BL/6n mouse model with cardiac function assessment Human genetics Medium 35050399
2021 DNAH9 protein is expressed in sperm tails, and loss-of-function variants in DNAH9 lead to significantly decreased DNAH9 mRNA and protein in sperm, causing outer dynein arm defects in sperm axoneme and severe asthenozoospermia without respiratory symptoms, establishing DNAH9 as required for flagellar motility. Whole exome sequencing, Sanger sequencing, TEM of sperm ultrastructure, qRT-PCR, immunofluorescence staining of sperm Reproductive biology and endocrinology : RB&E Medium 33610189
2024 Biallelic DNAH9 variants cause loss of outer dynein arms in sperm axoneme cross-sections and reduce expression of flagellar ultrastructure-related proteins DNAI1, DNAH1, and DNAH10, demonstrating that DNAH9 is required for proper assembly or stability of the outer dynein arm complex in flagella. Transmission electron microscopy of sperm axoneme, immunofluorescence showing reduced DNAI1, DNAH1, and DNAH10 expression in DNAH9 variant patients Journal of human genetics Medium 39523437
2025 A novel DNAH9 splice-site mutation (c.3743+1G>T) leads to abnormal splicing, as demonstrated by minigene analysis, establishing that correct splicing of DNAH9 pre-mRNA is required for functional protein production. Minigene splicing assay, in silico splice prediction, Sanger sequencing Molecular medicine reports Low 40376972

Source papers

Stage 0 corpus · 14 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2005 Mislocalization of DNAH5 and DNAH9 in respiratory cells from patients with primary ciliary dyskinesia. American journal of respiratory and critical care medicine 231 15750039
2018 Mutations in Outer Dynein Arm Heavy Chain DNAH9 Cause Motile Cilia Defects and Situs Inversus. American journal of human genetics 101 30471717
2001 Axonemal beta heavy chain dynein DNAH9: cDNA sequence, genomic structure, and investigation of its role in primary ciliary dyskinesia. Genomics 38 11247663
2021 Novel variants in DNAH9 lead to nonsyndromic severe asthenozoospermia. Reproductive biology and endocrinology : RB&E 28 33610189
2022 Dnah9 mutant mice and organoid models recapitulate the clinical features of patients with PCD and provide an excellent platform for drug screening. Cell death & disease 19 35729109
2016 Interaction between the DNAH9 gene and early smoke exposure in bronchial hyperresponsiveness. The European respiratory journal 18 26797031
2022 Biallelic DNAH9 mutations are identified in Chinese patients with defective left-right patterning and cilia-related complex congenital heart disease. Human genetics 14 35050399
2022 A Novel DNAH9 Gene Mutation Causing Primary Ciliary Dyskinesia With an Unusual Association of Jejunal Atresia in a Bahraini Child. Cureus 4 36712782
2024 Novel variants in DNAH9 are present in two infertile patients with severe asthenospermia. Journal of human genetics 3 39523437
2021 Whole-exome sequencing reveals a combination of extremely rare single-nucleotide polymorphism of DNAH9 and RSPH1 genes in a Japanese fetus with situs viscerum inversus. Medical molecular morphology 3 34008076
2025 DNAH9 variants in children with post-infectious bronchiolitis/bronchitis obliterans. Orphanet journal of rare diseases 1 40065384
2025 Novel compound heterozygous mutation in DNAH9 causes complex congenital heart disease. Molecular medicine reports 1 40376972
2022 Fetal Congenital Heart Disease Caused by Compound Heterozygous Mutations in the DNAH9 Gene: A Case Report. Frontiers in genetics 1 35116053
2015 Characterization and genomic structure of Dnah9, and its roles in nodal signaling pathways in the Japanese flounder (Paralichthys olivaceus). Fish physiology and biochemistry 0 26377939

Missed literature

Know a paper Affinage missed for DNAH9? Flag it for the maintainers and the community.

No submissions yet.