The Germline-Restricted Chromosome of Male Zebra Finches in Meiotic Prophase I: A Proteinaceous Scaffold and Chromatin Modifications
Among eukaryotes, there are many examples of partial genome elimination during ontogenesis. A striking example of this phenomenon is the loss of entire avian chromosomes during meiosis, called a germline-restricted chromosome (GRC). The GRC is absent in somatic tissues but present in germ cells. It...
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2024-11-01
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| author | Sergey Matveevsky |
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| description | Among eukaryotes, there are many examples of partial genome elimination during ontogenesis. A striking example of this phenomenon is the loss of entire avian chromosomes during meiosis, called a germline-restricted chromosome (GRC). The GRC is absent in somatic tissues but present in germ cells. It has been established that a prophase I male GRC is usually represented by a univalent surrounded by heterochromatin. In the present study, an immunocytochemical analysis of zebra finch spermatocytes was performed to focus on some details of this chromosome’s organization. For the first time, it was shown that a prophase I GRC contains the HORMAD1 protein, which participates in the formation of a full axial element. This GRC axial element has signs of a delay of core protein loading, probably owing to peculiarities of meiotic silencing of chromatin. The presence of repressive marks (H3K9me3 and H3K27me3) and the lack of RNA polymerase II, typically associated with active transcription, indicate transcriptional inactivation in the GRC body, despite the known activity of some genes of the GRC. Nevertheless, RPA and RAD51 proteins were found at some GRC sites, indicating the formation and repair of double-strand breaks on this chromosome. Our results provide new insights into the meiotic behavior and structure of a GRC. |
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| spelling | doaj-art-2f295b4858f542a68c18a60c8a5525332025-08-20T01:53:52ZengMDPI AGAnimals2076-26152024-11-011422324610.3390/ani14223246The Germline-Restricted Chromosome of Male Zebra Finches in Meiotic Prophase I: A Proteinaceous Scaffold and Chromatin ModificationsSergey Matveevsky0Vavilov Institute of General Genetics, Russian Academy of Sciences, 119991 Moscow, RussiaAmong eukaryotes, there are many examples of partial genome elimination during ontogenesis. A striking example of this phenomenon is the loss of entire avian chromosomes during meiosis, called a germline-restricted chromosome (GRC). The GRC is absent in somatic tissues but present in germ cells. It has been established that a prophase I male GRC is usually represented by a univalent surrounded by heterochromatin. In the present study, an immunocytochemical analysis of zebra finch spermatocytes was performed to focus on some details of this chromosome’s organization. For the first time, it was shown that a prophase I GRC contains the HORMAD1 protein, which participates in the formation of a full axial element. This GRC axial element has signs of a delay of core protein loading, probably owing to peculiarities of meiotic silencing of chromatin. The presence of repressive marks (H3K9me3 and H3K27me3) and the lack of RNA polymerase II, typically associated with active transcription, indicate transcriptional inactivation in the GRC body, despite the known activity of some genes of the GRC. Nevertheless, RPA and RAD51 proteins were found at some GRC sites, indicating the formation and repair of double-strand breaks on this chromosome. Our results provide new insights into the meiotic behavior and structure of a GRC.https://www.mdpi.com/2076-2615/14/22/3246germline-restricted chromosome<i>Taeniopygia guttata</i>synaptonemal complexmeiosisHORMAD1RPA |
| spellingShingle | Sergey Matveevsky The Germline-Restricted Chromosome of Male Zebra Finches in Meiotic Prophase I: A Proteinaceous Scaffold and Chromatin Modifications Animals germline-restricted chromosome <i>Taeniopygia guttata</i> synaptonemal complex meiosis HORMAD1 RPA |
| title | The Germline-Restricted Chromosome of Male Zebra Finches in Meiotic Prophase I: A Proteinaceous Scaffold and Chromatin Modifications |
| title_full | The Germline-Restricted Chromosome of Male Zebra Finches in Meiotic Prophase I: A Proteinaceous Scaffold and Chromatin Modifications |
| title_fullStr | The Germline-Restricted Chromosome of Male Zebra Finches in Meiotic Prophase I: A Proteinaceous Scaffold and Chromatin Modifications |
| title_full_unstemmed | The Germline-Restricted Chromosome of Male Zebra Finches in Meiotic Prophase I: A Proteinaceous Scaffold and Chromatin Modifications |
| title_short | The Germline-Restricted Chromosome of Male Zebra Finches in Meiotic Prophase I: A Proteinaceous Scaffold and Chromatin Modifications |
| title_sort | germline restricted chromosome of male zebra finches in meiotic prophase i a proteinaceous scaffold and chromatin modifications |
| topic | germline-restricted chromosome <i>Taeniopygia guttata</i> synaptonemal complex meiosis HORMAD1 RPA |
| url | https://www.mdpi.com/2076-2615/14/22/3246 |
| work_keys_str_mv | AT sergeymatveevsky thegermlinerestrictedchromosomeofmalezebrafinchesinmeioticprophaseiaproteinaceousscaffoldandchromatinmodifications AT sergeymatveevsky germlinerestrictedchromosomeofmalezebrafinchesinmeioticprophaseiaproteinaceousscaffoldandchromatinmodifications |