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Molecular adaptation to resistance exercise
Published in Adam P. Sharples, James P. Morton, Henning Wackerhage, Molecular Exercise Physiology, 2022
Beyond the acute regulation of the activity of the ribosome (the amount of protein synthesized per mRNA), mTORC1 can also regulate the number of ribosomes, or the translational capacity of the cell. mTORC1 regulates ribosome mass through the phosphorylation of a key ribosomal RNA transcription factor (upstream binding factor; UBF) and the preferential translation of ribosomal proteins. The transcription of ribosomal DNA is so essential to the function of cells that it has a specialized RNA polymerase (POL I) whose only role is to translate rDNA into the 47S pre-ribosomal RNA. The polycistronic 47S rRNA is then cleaved into the mature 5, 5.8, 18 and 28S rRNAs that make up ~80% of all the RNA in a mammalian cell (53). The transcription of rDNA is thought to be the first step in ribosome biogenesis (the production of new ribosomes) and this process is regulated by the protooncogene myc, and the transcription factors SL1 and UBF. Important for the regulation of ribosome biogenesis in response to resistance exercise, myc transcription increases, and the transcriptional activity of UBF is increased in response to phosphorylation by S6K1. In fact, activation of S6K1 is enough to drive ribosome biogenesis (54). So, following resistance exercise, UBF phosphorylation increases in relation to increased ribosomal RNA synthesis (52).
Diamond–Blackfan Anemia
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
Use of linkage analysis, candidate gene sequencing, whole-genome sequencing and microarray-based comparative genomic hybridization enabled identification of the RPS19 gene in 1999, and other related genes in the following years. It is apparent that nearly 70% of DBA cases are caused by mutations in the genes encoding RP of the small (e.g., RPS7, RPS10, RPS15A, RPS17, RPS19, RPS24, RPS26, RPS27, RPS28, RPS29) and large (e.g., RPL5, RPL11, RPL15, RPL18, RPL26, RPL27, RPL31, RPL35, RPL35A) subunits, leading to pre-ribosomal RNA (rRNA) maturation defects such as faulty ribosome biogenesis and/or inability of ribosomes to properly translate mRNA into protein. In particular, mutations in RPS19 (25%), RPL5 (9%), RPL11 (6.5%), RPL10 (6.4%), RPL35A (3.5%), RPS26 (2.6%), and RPS24 (2%) represent the most common causes of DBA (Table 67.1) [4–7].
Nonhistone Nuclear Phosphoproteins
Published in Lubomir S. Hnilica, Chromosomal Nonhistone Proteins, 2018
The nucleolus is the site of synthesis of ribosomal RNA as well as the location of ribosome precursor assembly and processing.119 Since the genes for preribosomal RNA are located exclusively in the nucleolus, it contains a specific fraction of chromatin enriched in rRNA cistrons. Therefore, this subnuclear organelle offers unique opportunities for studying the biochemical and morphological events accompanying gene activation, ribosome precursor assembly and processing, and the mechanisms involved in their control.
Pronuclear pattern does not predict morphokinetics behavior in human embryos
Published in Gynecological Endocrinology, 2018
Azita Faramarzi, Mohammad Ali Khalili, Marjan Omidi, Azam Agha-Rahimi, Fatemeh Taheri
Embryo selection procedure depends on various morphological characteristics of the embryos [6]. One of the characteristics is based on the assessment of pronuclear pattern. After fertilization, various morphological changes happen such as time-dependent NPBs appearance, migration and incorporation happens into nucleoli [7]. Nucleoli are the loci of the pre- ribosomal RNA (rRNA) synthesis and rRNA is vital for the translation of embryonic genome [8]. NPBs polarization may design one of the essential steps of embryo development, the embryonic axis. However, pronuclei rotate and position their axis to the second PB and attain an appropriate orientation for subsequent divisions. Changes in any of these regulated events may reason the embryo development disturbances [7]. The first study that evaluated day 1 including PN pattern as an indicator developmental potential of human embryos was done by Scott and Smith [9]. Yet, PN morphology evaluation, Z scoring, has been a subject of controversy [6,7,9–13].
Higher-risk myelodysplastic syndromes with del(5q): does the del(5q) matter?
Published in Expert Review of Hematology, 2020
Elan Gorshein, Urs M Weber, Steven Gore
Haploinsufficiency of ribosomal protein S14 (RPS14) is critical to the development of anemia in MDS with del(5q), resulting in an inability to process pre-ribosomal RNA and leading to abnormal erythroid differentiation [61]. Mouse models with heterozygous inactivation of RPS14 develop a macrocytic anemia similar to what may be seen in del(5q) [62]. Whether haploinsufficiency of RPS14 has a role in progression of MDS to AML is unclear.
Differential expression of snoRNAs in oral squamous cell carcinomas: new potential diagnostic markers
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2018
Cintia Chamorro-Petronacci, Mario Perez-Sayáns, Maria Elena Padín-Iruegas, Xabier Marichalar-Mendia, Mercedes Gallas-Torreira, Abel García García
The function of the snoRNA C/D and H/ACA box is developed in preribosomal RNA, modifying nucleotides at specific locations. The members of the C/D box are involved in 2’-O-methilation and those of the H/ACA box in pseudouridylation.