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Acosta-Cárdenas J, Jiménez-García LF, Cruz-Gómez SDJ, Mendoza-von der Borch AP, Segura-Valdez MDL. Microscopic Analysis of Nuclear Speckles in a Viviparous Reptile. Int J Mol Sci 2024; 25:5281. [PMID: 38791320 PMCID: PMC11120696 DOI: 10.3390/ijms25105281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/10/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
Nuclear speckles are compartments enriched in splicing factors present in the nucleoplasm of eucaryote cells. Speckles have been studied in mammalian culture and tissue cells, as well as in some non-mammalian vertebrate cells and invertebrate oocytes. In mammals, their morphology is linked to the transcriptional and splicing activities of the cell through a recruitment mechanism. In rats, speckle morphology depends on the hormonal cycle. In the present work, we explore whether a similar situation is also present in non-mammalian cells during the reproductive cycle. We studied the speckled pattern in several tissues of a viviparous reptile, the lizard Sceloporus torquatus, during two different stages of reproduction. We used immunofluorescence staining against splicing factors in hepatocytes and oviduct epithelium cells and fluorescence and confocal microscopy, as well as ultrastructural immunolocalization and EDTA contrast in Transmission Electron Microscopy. The distribution of splicing factors in the nucleoplasm of oviductal cells and hepatocytes coincides with the nuclear-speckled pattern described in mammals. Ultrastructurally, those cell types display Interchromatin Granule Clusters and Perichromatin Fibers. In addition, the morphology of speckles varies in oviduct cells at the two stages of the reproductive cycle analyzed, paralleling the phenomenon observed in the rat. The results show that the morphology of speckles in reptile cells depends upon the reproductive stage as it occurs in mammals.
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Affiliation(s)
- Jeniffer Acosta-Cárdenas
- Laboratorio de Nanobiología Celular, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México—UNAM, Mexico City 04510, Mexico; (J.A.-C.); (L.F.J.-G.); (S.d.J.C.-G.); (A.P.M.-v.d.B.)
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Luis Felipe Jiménez-García
- Laboratorio de Nanobiología Celular, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México—UNAM, Mexico City 04510, Mexico; (J.A.-C.); (L.F.J.-G.); (S.d.J.C.-G.); (A.P.M.-v.d.B.)
| | - Sarai de Jesús Cruz-Gómez
- Laboratorio de Nanobiología Celular, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México—UNAM, Mexico City 04510, Mexico; (J.A.-C.); (L.F.J.-G.); (S.d.J.C.-G.); (A.P.M.-v.d.B.)
| | - Ana Paulina Mendoza-von der Borch
- Laboratorio de Nanobiología Celular, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México—UNAM, Mexico City 04510, Mexico; (J.A.-C.); (L.F.J.-G.); (S.d.J.C.-G.); (A.P.M.-v.d.B.)
| | - María de Lourdes Segura-Valdez
- Laboratorio de Nanobiología Celular, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México—UNAM, Mexico City 04510, Mexico; (J.A.-C.); (L.F.J.-G.); (S.d.J.C.-G.); (A.P.M.-v.d.B.)
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Alexander KA, Yu R, Skuli N, Coffey NJ, Nguyen S, Faunce C, Huang H, Dardani IP, Good AL, Lim J, Li C, Biddle N, Joyce EF, Raj A, Lee D, Keith B, Simon MC, Berger SL. Nuclear speckles regulate HIF-2α programs and correlate with patient survival in kidney cancer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.14.557228. [PMID: 37745397 PMCID: PMC10515914 DOI: 10.1101/2023.09.14.557228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Nuclear speckles are membrane-less bodies within the cell nucleus enriched in RNA biogenesis, processing, and export factors. In this study we investigated speckle phenotype variation in human cancer, finding a reproducible speckle signature, based on RNA expression of speckle-resident proteins, across >20 cancer types. Of these, clear cell renal cell carcinoma (ccRCC) exhibited a clear correlation between the presence of this speckle expression signature, imaging-based speckle phenotype, and clinical outcomes. ccRCC is typified by hyperactivation of the HIF-2α transcription factor, and we demonstrate here that HIF-2α drives physical association of a select subset of its target genes with nuclear speckles. Disruption of HIF-2α-driven speckle association via deletion of its speckle targeting motifs (STMs)-defined in this study-led to defective induction of speckle-associating HIF-2α target genes without impacting non-speckle-associating HIF-2α target genes. We further identify the RNA export complex, TREX, as being specifically altered in speckle signature, and knockdown of key TREX component, ALYREF, also compromises speckle-associated gene expression. By integrating tissue culture functional studies with tumor genomic and imaging analysis, we show that HIF-2α gene regulatory programs are impacted by specific manipulation of speckle phenotype and by abrogation of speckle targeting abilities of HIF-2α. These findings suggest that, in ccRCC, a key biological function of nuclear speckles is to modulate expression of a specific subset of HIF-2α-regulated target genes that, in turn, influence patient outcomes. We also identify STMs in other transcription factors, suggesting that DNA-speckle targeting may be a general mechanism of gene regulation.
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Affiliation(s)
- Katherine A. Alexander
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Ruofan Yu
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Nicolas Skuli
- Department of Cell and Developmental Biology, Perelman School of Medicine, Philadelphia, PA 19104, USA
- Stem Cell and Xenograft Core, Department of Medicine – Division of Hematology and Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nathan J. Coffey
- Department of Cell and Developmental Biology, Perelman School of Medicine, Philadelphia, PA 19104, USA
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Son Nguyen
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christine Faunce
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Hua Huang
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Ian P. Dardani
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Austin L. Good
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joan Lim
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Catherine Li
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Nicholas Biddle
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Eric F. Joyce
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Arjun Raj
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Daniel Lee
- Division of Urology, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Brian Keith
- Department of Cell and Developmental Biology, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - M. Celeste Simon
- Department of Cell and Developmental Biology, Perelman School of Medicine, Philadelphia, PA 19104, USA
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shelley L. Berger
- Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
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