The platypus and echidna are the only extant species belonging to the clade of monotremata, the most basal mammalian lineage. The platypus is particularly well known for its mix of mammalian and reptilian characteristics and work in recent years has revealed this also extends to the genetic level. Amongst the monotreme specific features is the unique multiple sex chromosome system (5X4Y in the echidna and 5X5Y in the platypus), which forms a chain in meiosis. This raises questions about sex chromosome organisation at meiosis, including whether there has been changes in genes coding for synaptonemal complex proteins which are involved in homologous synapsis. Here we investigate the key structural components of the synaptonemal complex in platypus and echidna, synaptonemal complex proteins 1, 2 and 3 (SYCP1, SYCP2 and SYCP3). SYCP1 and SYCP2 orthologues are present, conserved and expressed in platypus testis. SYCP3 in contrast is highly diverged, but key residues required for self-association are conserved, while those required for tetramer stabilisation and DNA binding are missing. We also discovered a second SYCP3-like gene (SYCP3-like) in the same region. Comparison with the recently published Y-borne SYCP3 amino acid sequences revealed that SYCP3Y is more similar to SYCP3 in other mammals than the monotreme autosomal SYCP3. It is currently unclear if these changes in the SYCP3 gene repertoire are related to meiotic organisation of the extraordinary monotreme sex chromosome system.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.gene.2015.04.089 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Deletion of Ovary-Specific Transcript Causes Dysfunction of Meiosis and Derepress of DNA Transposons in Zebrafish Ovaries.
Biology (Basel)
December 2024
Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Hubei Hongshan Laboratory, Chinese Academy of Sciences, Wuhan 430072, China.
Alternative splicing of (DEAD-box helicase 4), a key germline marker gene, has been reported to generate sex-specific transcripts in zebrafish gonads. The biological functions and regulatory mechanisms of the ovary-specific transcript () during oogenesis remain unclear. In this study, we found that mutants, in which was specifically deleted, had enlarged ovaries but laid fewer eggs, along with having a lower fertilization rate compared to WT controls.
View Article and Find Full Text PDFThe centromere effect (CE) is a meiotic phenomenon that ensures meiotic crossover suppression in pericentromeric regions. Despite being a critical safeguard against nondisjunction, the mechanisms behind the CE remain unknown. Previous studies have shown that various regions of the pericentromere, encompassing proximal euchromatin, beta and alpha heterochromatin, undergo varying levels of crossover suppression, raising the question of whether distinct mechanisms establish the CE in these different regions.
View Article and Find Full Text PDFThe ATPase activity of yeast chromosome axis protein Hop1 affects the frequency of meiotic crossovers.
Nucleic Acids Res
December 2024
Department of Biochemistry, Indian Institute of Science, CV Raman Road, Bengaluru 560012, India.
Saccharomyces cerevisiae meiosis-specific Hop1, a structural constituent of the synaptonemal complex, also facilitates the formation of programmed DNA double-strand breaks and the pairing of homologous chromosomes. Here, we reveal a serendipitous discovery that Hop1 possesses robust DNA-independent ATPase activity, although it lacks recognizable sequence motifs required for ATP binding and hydrolysis. By leveraging molecular docking combined with molecular dynamics simulations and biochemical assays, we identified an ensemble of five amino acid residues in Hop1 that could potentially participate in ATP-binding and hydrolysis.
View Article and Find Full Text PDFIdentification of the Polo-like kinase substrate required for homologous synapsis.
J Cell Biol
March 2025
Department of Biology, Johns Hopkins University, Baltimore, MD, USA.
The synaptonemal complex (SC) is a zipper-like protein structure that aligns homologous chromosome pairs and regulates recombination during meiosis. Despite its conserved appearance and function, how synapsis occurs between chromosome axes remains elusive. Here, we demonstrate that Polo-like kinases (PLKs) phosphorylate a single conserved residue in the disordered C-terminal tails of two paralogous SC subunits, SYP-5 and SYP-6, to establish an electrostatic interface between the SC central region and chromosome axes in C.
View Article and Find Full Text PDFSpermatogenesis and sperm ultrastructure of the squid, Todarodes pacificus (Cephalopoda: Ommastrephidae).
Micron
February 2025
Department of Aqualife Medicine, Chonnam National University, Yeosu 59626, Republic of Korea. Electronic address:
Article Synopsis
- - The study focuses on spermatogenesis in Todarodes pacificus, identifying four stages: spermatogonium, spermatocyte, spermatid, and mature sperm.
- - Key characteristics of each stage are noted, including changes in karyoplasm and the development of structures such as mitochondria and proacrosomal vesicles during spermiogenesis.
- - Mature sperm are detailed with a specific nucleus size, irregular karyoplasm shape, and distinct acrosome and flagellum structures essential for function.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!