Publications by authors named "Tomer-Avidor Reiss"

The centrosome is a conserved characteristic of eukaryotic and human cells but is highly specialized in reproductive cells. The spermatozoan centrosome includes a slightly modified proximal centriole, an atypical distal centriole, and specialized pericentriolar material, including striated columns and capitellum. We investigated the localization of canonical centriolar proteins CEP44 and CCDC15 in human spermatozoa.

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There is a well-established link between abnormal sperm chromatin states and poor motility, however, how these two processes are interdependent is unknown. Here, we identified a possible mechanistic insight by showing that Protamine 2, a nuclear DNA packaging protein in sperm, directly interacts with cytoskeletal protein Septin 12, which is associated with sperm motility. Septin 12 has several isoforms, and we show, that in the sperm, the short one (Mw 36 kDa) is mis-localized, while two long isoforms (Mw 40 and 41 kDa) are unexpectedly lost in sperm chromatin-bound protein fractions.

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Family with sequence similarity 161 (Fam161) is an ancient family of microtubule-binding proteins located at the centriole and cilium transition zone (TZ) lumen that exhibit rapid evolution in mice. However, their adaptive role is unclear. Here, we used flies to gain insight into their cell type-specific adaptations.

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There is a well-established link between abnormal sperm chromatin states and poor motility, however, how these two processes are interdependent is unknown. Here, we identified a possible mechanistic insight by showing that Protamine 2, a nuclear DNA packaging protein in sperm, directly interacts with cytoskeletal protein Septin 12, which is associated with sperm motility. Septin 12 has several isoforms, and we show, that in the sperm, the short one (Mw 36 kDa) is mislocalized, while two long isoforms (Mw 40 and 41 kDa) are unexpectedly lost in sperm chromatin-bound protein fractions.

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Centrioles form centrosomes that organize microtubules, assist in cell structure, and nucleate cilia that provide motility and sensation. Within the sperm, the centrosome consists of two centrioles (proximal and distal centriole) and a pericentriolar material known as the striated column and capitulum. The distal centriole nucleates the flagellum.

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Centrioles are subcellular organelles found at the cilia base with an evolutionarily conserved structure and a shock absorber-like function. In sperm, centrioles are found at the flagellum base and are essential for embryo development in basal animals. Yet, sperm centrioles have evolved diverse forms, sometimes acting like a transmission system, as in cattle, and sometimes becoming dispensable, as in house mice.

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The mechanisms underlying male infertility are poorly understood. Most mammalian spermatozoa have two centrioles: the typical barrel-shaped proximal centriole (PC) and the atypical fan-like distal centriole (DC) connected to the axoneme (Ax). These structures are essential for fertility.

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A prominent technical barrier when imaging swimming sperm is capturing a singular sperm cell's head and tail position simultaneously at a high resolution to understand their relationship in different stages of the sperm tail beating cycle. This is due to the sperm's high beating frequency, rotational movement, and the large difference in diameter between the head and tail. These intricacies increase the complexity of determining the position of a dynamic subcellular structure in the sperm neck, such as the centriole.

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Article Synopsis
  • Centrosomes are crucial for organizing microtubules in cells, with sperm containing a specialized structure made up of different centrioles and pericentriolar material.
  • Researchers studied the localization of centriole proteins CEP135 and CP110 in cattle and human sperm, both of which play roles in centriole structure and cilia formation.
  • The antibodies used in the study identified CEP135 and CP110 near the expected locations in sperm centrioles, highlighting the unique functions of centrosomes in sperm development.
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The prevailing assumption has been that the human spermatozoon provides only one centriole to the zygote: the proximal centriole, with a canonical, cylinder-like shape. This overly simplistic view has come under challenge since discovering that the human spermatozoon provides a second, atypical centriole to the zygote. The study of human zygotes is challenging for ethical reasons, and bovine zygotes provide an important model due to a similarity in centrosome embryonic inherence and function.

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Article Synopsis
  • The study investigates global practices and challenges in using sperm DNA fragmentation (SDF) assays, which can affect male reproductive potential, as outlined in the latest WHO manual.
  • A survey of 436 reproductive clinicians revealed that the most popular SDF assay is TUNEL, with a significant influence from availability on their choices.
  • Clinicians see the value of SDF testing in understanding infertility but face barriers like insufficient professional guidelines and a lack of accepted reference values for interpreting SDF results.
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Article Synopsis
  • AI has rapidly advanced in medicine, particularly benefiting fields like andrology and reproductive medicine through technologies like machine learning and neural networks.
  • AI tools can enhance the diagnosis and treatment of male infertility, improve patient care accuracy, and increase efficiency in clinical management and research.
  • Future advancements in AI integration are expected to lead to significant breakthroughs and improvements in evidence-based practices within andrology and reproductive medicine.
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Centrioles are microtubule-based, barrel-shaped, subcellular organelles with evolutionarily conserved composition, structure, and function. Yet, in sperm cells, centrioles are remodeled, gaining species-specific composition and structure. The sperm centrioles of undergo dramatic remodeling, during which most known centriolar proteins are lost.

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Centrosome formation during early development in mice and rats occurs due to the appearance of centrioles de novo. In contrast, in humans and other non-rodent mammals, centrioles are thought to be derived from spermatozoa. Ultrastructural study of zygotes and early embryos of cattle at full series of ultrathin sections show that the proximal centriole of the spermatozoon disappears by the end of the first cleavage division.

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Article Synopsis
  • The study investigates global practices for managing sperm DNA fragmentation (SDF) in infertile men, highlighting its impact on fertility and assisted reproductive technology (ART).
  • A survey collecting data from 436 reproductive experts across 55 countries revealed a common recommendation for lifestyle changes and antioxidants, with varying durations for treatment and differing management approaches for specific infertility cases.
  • The findings indicate a lack of uniformity in practices, emphasizing the need for standardized guidelines and expert consensus for treating men with elevated SDF.
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Article Synopsis
  • Infertility is a global issue affecting about 186 million people, with male factors contributing to around half of all cases, indicating a growing prevalence of male infertility over the past 40 years.
  • The field of Andrology, which focuses on male reproductive health, has faced challenges due to cultural neglect regarding male partners in infertility diagnosis and treatment, and reliance on assisted reproductive techniques (ART) may overlook the importance of male gamete quality.
  • Recent advancements in Andrology, including research on genetics, oxidative stress, and innovative technologies like artificial intelligence and gene engineering, highlight a critical need for further studies to better understand male infertility and improve ART outcomes.
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Sperm cells have intrigued biologists since they were first observed nearly 350 years ago by Antonie van Leeuwenhoek and Johan Ham [...

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The centrosome consists of two centrioles surrounded by pericentriolar material [...

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Sperm cells are transcriptionally and translationally silent. Therefore, they may use one of the remaining mechanisms to respond to stimuli in their environment, the post-translational modification of their proteins. Here we examined three post-translational modifications, acetylation, glutamylation, and glycylation of the protein tubulin in human and cattle sperm.

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Unexplained infertility affects about one-third of infertile couples and is defined as the failure to identify the cause of infertility despite extensive evaluation of the male and female partners. Therefore, there is a need for a multiparametric approach to study sperm function. Recently, we developed a Fluorescence-Based Ratiometric Analysis of Sperm Centrioles (FRAC) assay to determine sperm centriole quality.

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Centrioles are subcellular organelles essential for normal cell function and development; they form the cell's centrosome (a major cytoplasmic microtubule organization center) and cilium (a sensory and motile hair-like cellular extension). Centrioles with evolutionarily conserved characteristics are found in most animal cell types but are absent in egg cells and exhibit unexpectedly high structural, compositional, and functional diversity in sperm cells. As a result, the centriole's precise role in fertility and early embryo development is unclear.

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The sperm competition theory, as proposed by Geoff Parker, predicts that sperm evolve through a cascade of changes. As an example, internal fertilization is followed by sperm morphology diversification. However, little is known about the evolution of internal sperm structures.

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