A loss-of-function variant in DNA mismatch repair gene MLH3 underlies severe oligozoospermia

Nawaz, Shoaib; Ullah, Muhammad Imran; Hamid, Beenish Samreen; Nargis, Jalwa; Nawaz, Mehboob; Hussain, Shabir; Ahmad, Farooq

doi:10.1038/s10038-021-00907-z

Cited by 14 publications

(6 citation statements)

References 28 publications

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“…To assess sperm motility and morphology, the collected semen was liquefied at 37 °C for 30-60 minutes. A minimum of 1,000 spermatozoa were counted to analyze sperm motility by the CASA system using an MTG-GmbH analyzer (version 5.4; MTG-MedeaLAB) according to the unit’s standard operating procedures based on the WHO guidelines as previously reported (Krause et al , 2016; Nawaz et al , 2021; Slabbert et al , 2015). Sperm from liquified semen were subjected to PAP-staining and the morphology was microscopically analyzed according to the guidelines from WHO and evaluated by a reproductive medicine specialist.…”

Section: Methodsmentioning

confidence: 99%

LRRC23 truncation impairs radial spoke 3 head assembly and sperm motility underlying male infertility

Hwang

Chai

Nawaz

et al. 2023

Preprint

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Radial spokes (RSs) are T-shaped multiprotein complexes in the 9+2 axoneme of motile cilia and flagella that couple the central pair to the peripheral doublet microtubules. RS1, RS2, and RS3 are repeated along the outer microtubule of the axoneme and modulate the activity of dynein, thus ciliary and flagella movement. RS substructures are distinct in spermatozoa from other cells harboring motile cilia in mammals. However, the molecular components of the cell-type specific RS substructures remain largely unknown. Here, we report a leucine-rich repeat-containing protein, LRRC23, is a RS head component indispensable for the RS3 head assembly and flagellar movement in human and mouse sperm. From a Pakistani consanguineous family with infertile males due to reduced sperm motility, we identified a splice site variant of LRRC23 that leads to truncate LRRC23 at the C-terminus. In mutant mouse model mimicking the identified variant, the truncated LRRC23 protein is produced in testis but fails to localize in the mature sperm tail, causing severe sperm motility defects and male infertility. Purified recombinant human LRRC23 does not interacts with RS stalk proteins, but with a head protein, RSPH9, which is abolished by the C-terminus truncation of LRRC23. Cryo-electron tomography and sub-tomogram averaging unambiguously visualized that the RS3 head and sperm-specific RS2-RS3 bridge structure is missing in the LRRC23 mutant sperm. Our study provides new insights into RS3 structure and function in mammalian sperm flagella as well as molecular pathogenicity of LRRC23 underlying reduced sperm motility in infertile human males.

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Section: Methodsmentioning

confidence: 99%

LRRC23 truncation impairs radial spoke 3 head assembly and sperm motility underlying male infertility

Hwang

Chai

Nawaz

et al. 2023

Preprint

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“…Five individuals, including two affected (II‐3 and II‐5) and three unaffected (I‐1, I‐2 and III‐1) family members, provided blood samples for genetic testing (Figure 1). Genomic DNA was extracted from the peripheral blood samples and tested for Y‐chromosome microdeletions spanning four regions (AZFa, AZFb, AZFc and AZFd) as described previously 23,24 …”

Section: Methodsmentioning

confidence: 99%

A variant in sperm‐specific glycolytic enzyme enolase 4 (ENO4) causes human male infertility

Nawaz,

Hussain,

Bilal

et al. 2023

The Journal of Gene Medicine

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BackgroundAlthough defects in sperm morphology and physiology lead to male infertility, in many instances, the exact disruption of molecular pathways in a given patient is often unknown. The glycolytic pathway is an essential process to supply energy in sperm cell motility. Enolase 4 (ENO4) is crucial for the glycolytic process, which provides the energy for sperm cells in motility. ENO4 is located in the sperm principal piece and is essential for the motility and organization of the sperm flagellum. In the present study, we characterized a family with asthenozoospermia and abnormal sperm morphology as a result of a variant in the enolase 4 (ENO4) gene.MethodsComputer‐assisted semen analysis, papanicolaou smear staining and scanning electron microscopy were used to examine sperm motility and morphology for semen analysis in patients. For genetic analysis, whole‐exome sequencing followed by Sanger sequencing was performed.ResultsTwo brothers in a consanguineous family were being clinically investigated for sperm motility and morphology issues. Genetic analysis by whole‐exome sequencing revealed a homozygous variant [c.293A>G, p.(Lys98Arg)] in the ENO4 gene that segregated with infertility in the family, shared by affected but not controls.ConclusionsIn view of the association of asthenozoospermia and abnormal sperm morphology in Eno4 knockout mice, we consider this to be the first report describing the involvement of ENO4 gene in human male infertility. We also explore the possible involvement of another variant in explaining other phenotypic features in this family.

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“…To assess sperm motility and morphology, the collected semen was liquefied at 37 °C for 30–60 min. A minimum of 1000 spermatozoa were counted to analyze sperm motility by the CASA system using an MTG-GmbH analyzer (version 5.4; MTG-MedeaLAB) according to the unit’s standard operating procedures based on the WHO guidelines as previously reported ( Krause et al, 2016 ; Nawaz et al, 2021 ; Slabbert et al, 2015 ). Sperm from liquified semen were subjected to PAP-staining and the morphology was microscopically analyzed according to the guidelines from WHO and evaluated by a reproductive medicine specialist.…”

Section: Methodsmentioning

confidence: 99%

LRRC23 truncation impairs radial spoke 3 head assembly and sperm motility underlying male infertility

Hwang,

Chai,

Nawaz

et al. 2023

eLife

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Radial spokes (RS) are T-shaped multiprotein complexes on the axonemal microtubules. Repeated RS1, RS2, and RS3 couple the central pair to modulate ciliary and flagellar motility. Despite the cell type specificity of RS3 substructures, their molecular components remain largely unknown. Here, we report that a leucine-rich repeat-containing protein, LRRC23, is an RS3 head component essential for its head assembly and flagellar motility in mammalian spermatozoa. From infertile male patients with defective sperm motility, we identified a splice site variant of LRRC23. A mutant mouse model mimicking this variant produces a truncated LRRC23 at the C-terminus that fails to localize to the sperm tail, causing male infertility due to defective sperm motility. LRRC23 was previously proposed to be an ortholog of the RS stalk protein RSP15. However, we found that purified recombinant LRRC23 interacts with an RS head protein RSPH9, which is abolished by the C-terminal truncation. Our comparative sequence analyses also showed that LRRC34, not LRRC23, is the RSP15 ortholog. Cryo-electron tomography clearly revealed that the absence of the RS3 head and the sperm-specific RS2-RS3 bridge structure in LRRC23 mutant spermatozoa. Our study provides new insights into the structure and function of RS3 in mammalian spermatozoa and the molecular pathogenicity of LRRC23 underlying reduced sperm motility in infertile human males.

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A loss-of-function variant in DNA mismatch repair gene MLH3 underlies severe oligozoospermia

Cited by 14 publications

References 28 publications

LRRC23 truncation impairs radial spoke 3 head assembly and sperm motility underlying male infertility

LRRC23 truncation impairs radial spoke 3 head assembly and sperm motility underlying male infertility

A variant in sperm‐specific glycolytic enzyme enolase 4 (ENO4) causes human male infertility

LRRC23 truncation impairs radial spoke 3 head assembly and sperm motility underlying male infertility

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