The structural organization of the cell nucleus poses many intriguing questions. One of them is the organization of nuclear domains (ND), sharp-bordered nuclear compartments concentrating a range of nuclear proteins. In this study, we used the recently discovered B-body as a model to investigate the mechanisms governing the formation of NDs. The nuclear B-body forms in the cellular precursors of flight muscles in developing Drosophila pupae. Prior to myoblast fusion, the splicing factor Bruno (Bru) concentrates into a single, large B-body but transitions into multiple smaller speckles in a diffused nuclear pattern after the commencement of myogenesis. We hypothesized that the B-body must contain an RNA scaffold because Bru association with B-bodies is RNase-sensitive. Using Immuno-FISH, we identified a lncRNA co-localizing with the B-body; this RNA is the heat shock RNA omega (hsrω). Next, we tested the requirement of protein and RNA components for the integrity of the B-body. Genetic knockdown of the protein Bru did not perturb the size of B-body, as revealed by hsrω FISH. In contrast, when hsrω was removed via chromosomal deletions, the structural stability of the B-body was severely affected. Since hsrω is expressed in a broader range of tissues than Bru, we conducted a misexpression study to test if it is possible to reconstitute the B-body outside flight muscles. Nuclei of the midgut epithelium are similar to the polyploid nuclei to flight muscle progenitors that express hsrω; however, ectopically expressed Bru did not accumulate to form a B-body in them. Lastly, we found that flies with reduced hsrω showed normal IFM development, flight ability, and viability similar to their wild-type counterparts. In summary, our study demonstrates the importance of an RNA scaffolding for the B-body and highlights the importance of an additional mechanism to enable protein trafficking and accumulation at B-bodies. Meanwhile, the functional significance of B-bodies remains elusive and will require additional studies.
","abstract_html":"<p>The structural organization of the cell nucleus poses many intriguing questions. One of them is the organization of nuclear domains (ND), sharp-bordered nuclear compartments concentrating a range of nuclear proteins. In this study, we used the recently discovered B-body as a model to investigate the mechanisms governing the formation of NDs. The nuclear B-body forms in the cellular precursors of flight muscles in developing <em>Drosophila</em> pupae. Prior to myoblast fusion, the splicing factor Bruno (Bru) concentrates into a single, large B-body but transitions into multiple smaller speckles in a diffused nuclear pattern after the commencement of myogenesis. We hypothesized that the B-body must contain an RNA scaffold because Bru association with B-bodies is RNase-sensitive. Using Immuno-FISH, we identified a lncRNA co-localizing with the B-body; this RNA is the <em>heat shock RNA omega</em> (<em>hsrω</em>). Next, we tested the requirement of protein and RNA components for the integrity of the B-body. Genetic knockdown of the protein Bru did not perturb the size of B-body, as revealed by <em>hsrω</em> FISH. In contrast, when <em>hsrω</em> was removed via chromosomal deletions, the structural stability of the B-body was severely affected. Since <em>hsrω</em> is expressed in a broader range of tissues than Bru, we conducted a misexpression study to test if it is possible to reconstitute the B-body outside flight muscles. Nuclei of the midgut epithelium are similar to the polyploid nuclei to flight muscle progenitors that express <em>hsrω</em>; however, ectopically expressed Bru did not accumulate to form a B-body in them. Lastly, we found that flies with reduced <em>hsrω</em> showed normal IFM development, flight ability, and viability similar to their wild-type counterparts. In summary, our study demonstrates the importance of an RNA scaffolding for the B-body and highlights the importance of an additional mechanism to enable protein trafficking and accumulation at B-bodies. Meanwhile, the functional significance of B-bodies remains elusive and will require additional studies.</p>","abstract_has_math":false,"creators":["An, SooBin"],"institution":null,"degree_name":"Master of Science in Integrative Biology (MSIB)","degree_level":"Thesis","degree_discipline":"Biology","degree_department":null,"school":null,"contributors":["Brandon Carpenter","Susan M. Smith","Carol Chrestensen"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2023,"date_issued":"2023-05-03T07:00:00Z","date_published":"2023-05-03T07:00:00Z","updated_at":"2026-07-24T02:44:06Z","subjects":["nuclear domains","B-body","Bruno","Drosophila","nucleus","muscle development","lncRNA"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.kennesaw.edu/integrbiol_etd/95","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Brandon Carpenter","Susan M. 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One of them is the organization of nuclear domains (ND), sharp-bordered nuclear compartments concentrating a range of nuclear proteins. In this study, we used the recently discovered B-body as a model to investigate the mechanisms governing the formation of NDs. The nuclear B-body forms in the cellular precursors of flight muscles in developing Drosophila pupae. Prior to myoblast fusion, the splicing factor Bruno (Bru) concentrates into a single, large B-body but transitions into multiple smaller speckles in a diffused nuclear pattern after the commencement of myogenesis. We hypothesized that the B-body must contain an RNA scaffold because Bru association with B-bodies is RNase-sensitive. Using Immuno-FISH, we identified a lncRNA co-localizing with the B-body; this RNA is the heat shock RNA omega (hsrω). Next, we tested the requirement of protein and RNA components for the integrity of the B-body. Genetic knockdown of the protein Bru did not perturb the size of B-body, as revealed by hsrω FISH. In contrast, when hsrω was removed via chromosomal deletions, the structural stability of the B-body was severely affected. Since hsrω is expressed in a broader range of tissues than Bru, we conducted a misexpression study to test if it is possible to reconstitute the B-body outside flight muscles. Nuclei of the midgut epithelium are similar to the polyploid nuclei to flight muscle progenitors that express hsrω; however, ectopically expressed Bru did not accumulate to form a B-body in them. Lastly, we found that flies with reduced hsrω showed normal IFM development, flight ability, and viability similar to their wild-type counterparts. In summary, our study demonstrates the importance of an RNA scaffolding for the B-body and highlights the importance of an additional mechanism to enable protein trafficking and accumulation at B-bodies. Meanwhile, the functional significance of B-bodies remains elusive and will require additional studies.
"]},{"key":"dc:title","label":"Title","values":["Long non-coding RNA Hsr-omega provides scaffolding for the nuclear domain B-body"]}]}],"canonical_facts":{"dc:contributor":["Brandon Carpenter","Susan M. Smith","Carol Chrestensen"],"dc:creator":["An, SooBin"],"dc:date.available":["2024-05-07T07:00:00Z"],"dc:description.abstract":["The structural organization of the cell nucleus poses many intriguing questions. One of them is the organization of nuclear domains (ND), sharp-bordered nuclear compartments concentrating a range of nuclear proteins. In this study, we used the recently discovered B-body as a model to investigate the mechanisms governing the formation of NDs. The nuclear B-body forms in the cellular precursors of flight muscles in developing Drosophila pupae. Prior to myoblast fusion, the splicing factor Bruno (Bru) concentrates into a single, large B-body but transitions into multiple smaller speckles in a diffused nuclear pattern after the commencement of myogenesis. We hypothesized that the B-body must contain an RNA scaffold because Bru association with B-bodies is RNase-sensitive. Using Immuno-FISH, we identified a lncRNA co-localizing with the B-body; this RNA is the heat shock RNA omega (hsrω). Next, we tested the requirement of protein and RNA components for the integrity of the B-body. Genetic knockdown of the protein Bru did not perturb the size of B-body, as revealed by hsrω FISH. In contrast, when hsrω was removed via chromosomal deletions, the structural stability of the B-body was severely affected. Since hsrω is expressed in a broader range of tissues than Bru, we conducted a misexpression study to test if it is possible to reconstitute the B-body outside flight muscles. Nuclei of the midgut epithelium are similar to the polyploid nuclei to flight muscle progenitors that express hsrω; however, ectopically expressed Bru did not accumulate to form a B-body in them. Lastly, we found that flies with reduced hsrω showed normal IFM development, flight ability, and viability similar to their wild-type counterparts. In summary, our study demonstrates the importance of an RNA scaffolding for the B-body and highlights the importance of an additional mechanism to enable protein trafficking and accumulation at B-bodies. Meanwhile, the functional significance of B-bodies remains elusive and will require additional studies.
"],"dc:identifier":["https://digitalcommons.kennesaw.edu/integrbiol_etd/95"],"dc:subject":["nuclear domains","B-body","Bruno","Drosophila","nucleus","muscle development","lncRNA"],"dc:title":["Long non-coding RNA Hsr-omega provides scaffolding for the nuclear domain B-body"],"thesis:degree_discipline":["Biology"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Master of Science in Integrative Biology (MSIB)"]},"updated_at":"2026-07-24T02:44:06Z"}