2026-09-21T22:11:14Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/110832 2023-07-11 col_2142_5131 col_2142_14855 com_2142_5130 com_2142_14854 com_2142_14793 com_2142_8903

Kannanganattu, Prasanth V Kannanganattu, Prasanth V Prasanth, Supriya G Belmont, Andrew S Ceman, Stephanie Kalsotra, Auinash Hao, Qinyu 2021-09-17T04:04:32Z 2021-09-17T04:04:32Z 2023-09-17T04:07:01Z 2021-04-20 2021-05 Eukaryotic cell nucleus is compartmentalized into various non-membranous sub-nuclear domains with nucleolus being the most prominent one. The nucleolus is the largest sub-nuclear domain where ribosomal gene transcription, pre-rRNA processing, and the initial steps of ribosome sub-unit assembly take place. In human cells, nucleoli are formed around nucleolar organizer regions (NORs) located on the short arms of the five acrocentric chromosomes. NORs are composed of tandem copies of hundreds of rDNA repeats. However, the sequence beyond the rDNA array within the p-arms of NOR containing acrocentric chromosomes is largely unknown. In human cells, ~400 copies of rDNA repeats code for rRNAs. Interestingly, at any time point only ~50% of rRNA genes remain transcriptionally active. While the dynamic changes in histone or DNA modifications on rDNA regulatory elements, and noncoding RNAs have been implicated in regulating the transcription of individual rRNA genes, the precise mechanism of how ~50% of rRNA genes remains silenced at any time point is yet to understand. In Chapter II, I focus on the characterization of a novel abundant family of ncRNAs, Single NUcleolus Localized RNA (SNUL-RNA). SNUL-RNAs decorate individual nucleolus in the form of a ‘cloud’ in primary and transformed human cells. Super-resolution microscopy imaging revealed that SNUL-RNA showed similar nuclear distribution to pre-rRNA. Further studies suggested that SNUL-RNA is transcribed by RNA Pol I and behaves similarly to pre-rRNA during biological processes when the nucleolar structure is disrupted. Long-read RNA-sequencing analyses indicate that full-length SNULs show significant similarities to pre-rRNAs, implying that SNULs could be evolved from duplications of rDNA genes during evolution. Intriguingly, SNUL-RNAs are found to ‘coat’ the p-arm of NOR-containing chromosomes in a monoallelic fashion, and this monoallelic expression of SNUL-RNAs is epigenetically inheritable and potentially regulated by histone and DNA modifications. Loss-of-function studies reveal that SNUL-RNAs might play a negative regulatory role on rRNA biogenesis. My studies emphasized that not all nucleoli within a cell are functionally identical and NORs on different acrocentric chromosomes are distinct from each other. It also revealed a novel RNA-mediated mechanism for regulating rDNA gene expression and nucleolar function. Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2023-05-01 The student, Qinyu Hao, accepted the attached license on 2021-04-19 at 10:41. The student, Qinyu Hao, submitted this Dissertation for approval on 2021-04-19 at 11:03. This Dissertation was approved for publication on 2021-04-20 at 08:46. DSpace SAF Submission Ingestion Package generated from Vireo submission #16403 on 2021-09-16 at 20:10:45 Made available in DSpace on 2021-09-17T04:04:32Z (GMT). No. of bitstreams: 2 HAO-DISSERTATION-2021.pdf: 14979917 bytes, checksum: 72f20dd5a347b74bd3fc28d0bf951e6d (MD5) LICENSE.txt: 4206 bytes, checksum: 276cd0962efb90d42a391136faa95d34 (MD5) Previous issue date: 2021-04-20 Embargo set by: Seth Robbins for item 118677 Lift date: 2023-09-17T04:04:53Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system Embargo set by: Seth Robbins for item 118677 Lift date: 2023-09-17T04:07:01Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system Author requested closed access (OA after 2yrs) in Vireo ETD system Limited application/pdf http://hdl.handle.net/2142/110832 en Copyright 2021 Qinyu Hao SNUL-1 long non-coding RNA nucleolus rRNA biogenesis Characterization of a novel family of nucleolus localized RNAs text Thesis Cell & Developmental Biology Cell and Developmental Biology University of Illinois at Urbana-Champaign Dissertation Ph.D.