Novel selectively amplified DNA sequences in the germline genome of the Japanese hagfish, Eptatretus burgeri
Abstract In the Japanese hagfish Eptatretus burgeri, 16 chromosomes (eliminated [E]-chromosomes) have been lost in somatic cells (2n = 36), which is equivalent to approx. 21% of the genomic DNA in germ cells (2n = 52). At least seven of the 12 eliminated repetitive DNA families isolated in eight hag...
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Nature Portfolio
2022-12-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-022-26007-2 |
| _version_ | 1811204007123746816 |
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| author | Kohei Nagao Tomoko Otsuzumi Hitomi Chinone Takashi Sasaki Junko Yoshimoto Makiko Matsuda Souichirou Kubota Yuji Goto |
| author_facet | Kohei Nagao Tomoko Otsuzumi Hitomi Chinone Takashi Sasaki Junko Yoshimoto Makiko Matsuda Souichirou Kubota Yuji Goto |
| author_sort | Kohei Nagao |
| collection | DOAJ |
| description | Abstract In the Japanese hagfish Eptatretus burgeri, 16 chromosomes (eliminated [E]-chromosomes) have been lost in somatic cells (2n = 36), which is equivalent to approx. 21% of the genomic DNA in germ cells (2n = 52). At least seven of the 12 eliminated repetitive DNA families isolated in eight hagfish species were selectively amplified in the germline genome of this species. One of them, EEEb1 (eliminated element of E. burgeri 1) is exclusively localized on all E-chromosomes. Herein, we identified four novel eliminated repetitive DNA families (named EEEb3–6) through PCR amplification and suppressive subtractive hybridization (SSH) combined with Southern-blot hybridization. EEEb3 was mosaic for 5S rDNA and SINE elements. EEEb4 was GC-rich repeats and has one pair of direct and inverted repeats, whereas EEEb5 and EEEb6 were AT-rich repeats with one pair and two pairs of sub-repeats, respectively. Interestingly, all repeat classes except EEEb3 were transcribed in the testes, although no open reading frames (ORF) were identified. We conducted fluorescence in situ hybridization (FISH) to examine the chromosomal localizations of EEEb3–6 and EEEb2, which was previously isolated from the germline genome of E. burgeri. All sequences were only found on all EEEb1-positive E-chromosomes. Copy number estimation of the repeated elements by slot-blot hybridization revealed that (i) the EEEb1–6 family members occupied 39.9% of the total eliminated DNA, and (ii) a small number of repeats were retained in somatic cells, suggesting that there is incomplete elimination of the repeated elements. These results provide new insights into the mechanisms involved in the chromosome elimination and the evolution of E-chromosomes. |
| first_indexed | 2024-04-12T03:05:29Z |
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| id | doaj.art-eb5213816d874d91a3f9fa1a96c24215 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-04-12T03:05:29Z |
| publishDate | 2022-12-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-eb5213816d874d91a3f9fa1a96c242152022-12-22T03:50:32ZengNature PortfolioScientific Reports2045-23222022-12-0112111510.1038/s41598-022-26007-2Novel selectively amplified DNA sequences in the germline genome of the Japanese hagfish, Eptatretus burgeriKohei Nagao0Tomoko Otsuzumi1Hitomi Chinone2Takashi Sasaki3Junko Yoshimoto4Makiko Matsuda5Souichirou Kubota6Yuji Goto7Department of Biology, Faculty of Science, Toho UniversityDepartment of Biology, Faculty of Science, Toho UniversityDepartment of Biology, Faculty of Science, Toho UniversityDepartment of Biology, Faculty of Science, Toho UniversityDepartment of Biology, Faculty of Science, Toho UniversityDepartment of Biology, Faculty of Science, Toho UniversityDepartment of Biology, Faculty of Science, Toho UniversityDepartment of Biology, Faculty of Science, Toho UniversityAbstract In the Japanese hagfish Eptatretus burgeri, 16 chromosomes (eliminated [E]-chromosomes) have been lost in somatic cells (2n = 36), which is equivalent to approx. 21% of the genomic DNA in germ cells (2n = 52). At least seven of the 12 eliminated repetitive DNA families isolated in eight hagfish species were selectively amplified in the germline genome of this species. One of them, EEEb1 (eliminated element of E. burgeri 1) is exclusively localized on all E-chromosomes. Herein, we identified four novel eliminated repetitive DNA families (named EEEb3–6) through PCR amplification and suppressive subtractive hybridization (SSH) combined with Southern-blot hybridization. EEEb3 was mosaic for 5S rDNA and SINE elements. EEEb4 was GC-rich repeats and has one pair of direct and inverted repeats, whereas EEEb5 and EEEb6 were AT-rich repeats with one pair and two pairs of sub-repeats, respectively. Interestingly, all repeat classes except EEEb3 were transcribed in the testes, although no open reading frames (ORF) were identified. We conducted fluorescence in situ hybridization (FISH) to examine the chromosomal localizations of EEEb3–6 and EEEb2, which was previously isolated from the germline genome of E. burgeri. All sequences were only found on all EEEb1-positive E-chromosomes. Copy number estimation of the repeated elements by slot-blot hybridization revealed that (i) the EEEb1–6 family members occupied 39.9% of the total eliminated DNA, and (ii) a small number of repeats were retained in somatic cells, suggesting that there is incomplete elimination of the repeated elements. These results provide new insights into the mechanisms involved in the chromosome elimination and the evolution of E-chromosomes.https://doi.org/10.1038/s41598-022-26007-2 |
| spellingShingle | Kohei Nagao Tomoko Otsuzumi Hitomi Chinone Takashi Sasaki Junko Yoshimoto Makiko Matsuda Souichirou Kubota Yuji Goto Novel selectively amplified DNA sequences in the germline genome of the Japanese hagfish, Eptatretus burgeri Scientific Reports |
| title | Novel selectively amplified DNA sequences in the germline genome of the Japanese hagfish, Eptatretus burgeri |
| title_full | Novel selectively amplified DNA sequences in the germline genome of the Japanese hagfish, Eptatretus burgeri |
| title_fullStr | Novel selectively amplified DNA sequences in the germline genome of the Japanese hagfish, Eptatretus burgeri |
| title_full_unstemmed | Novel selectively amplified DNA sequences in the germline genome of the Japanese hagfish, Eptatretus burgeri |
| title_short | Novel selectively amplified DNA sequences in the germline genome of the Japanese hagfish, Eptatretus burgeri |
| title_sort | novel selectively amplified dna sequences in the germline genome of the japanese hagfish eptatretus burgeri |
| url | https://doi.org/10.1038/s41598-022-26007-2 |
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