Satellite non-coding RNAs: the emerging players in cells, cellular pathways and cancer

Abstract

For several decades, transcriptional inactivity was considered as one of the particular features of constitutive heterochromatin and, therefore, of its major component, satellite DNA sequences. However, more recently, succeeding evidences have demonstrated that these sequences can indeed be transcribed, yielding satellite non-coding RNAs with important roles in the organization and regulation of genomes. Since then, several studies have been conducted, trying to understand the function(s) of these sequences not only in the normal but also in cancer genomes. It is thought that the association between cancer and satncRNAs is mostly due to the influence of these transcripts in the genome instability, a hallmark of cancer. The few reports on satellite DNA transcription in cancer contexts point to its overexpression; however, this scenario may be far more complex, variable, and influenced by a number of factors and the exact role of satncRNAs in the oncogenic process remains poorly understood. The greater is the knowledge on the association of satncRNAs with cancer, the greater would be the opportunity to assist cancer treatment, either by the design of effective therapies targeting these molecules or by using them as biomarkers in cancer diagnosis, prognosis, and with predictive value.

Transcription of highly repetitive tandemly organized DNA in amphibians and birds: A historical overview and modern concepts

“…[3][4][5][6][7][8][9] Fundamental knowledge about biogenesis and functions of the satellite noncoding transcripts has found application in medicine. [8][9][10] It is thus clear that satellite DNAs and their transcripts possess essential structural and functional roles in the cell.…”

“…2,5,7,8,[10][11][12][13][14][15][16][17] However, the data on tandemly organized DNA repeats transcription in the amphibian and avian taxa is fragmentary and insufficiently represented in the literature. 18,19 Meanwhile, the amphibians and birds are promising model organisms to investigate the phenomena of satellite DNA transcription.…”

Centromeric Non-coding Transcription: Opening the Black Box of Chromosomal Instability?

“…Nonetheless, the transcription of centromeric sequences is a conserved feature of every eukaryote studied to date, including yeast, beetles, maize, Arabidopsis , flies, mice, marsupials and humans [36-44]. In fact, centromeric transcription was reported as early as 1968 [45] and 1973 [46]; however, this phenomenon was ignored until recently, with the blooming of non-coding RNAs findings [6]. Currently, experimental evidence supports the concept that correct chromosome segregation is hindered by the inhibition, degradation, or overexpression of centromeric sequences.…”

“…Nevertheless, the recent boom in studies of non-coding RNAs has enriched our understanding of the kinetochore and centromere function [5, 6]. Progress in this field has refuted the old conception that both the centromere and mitotic cells are transcriptionally silent [6].…”

“…Progress in this field has refuted the old conception that both the centromere and mitotic cells are transcriptionally silent [6]. It has been demonstrated that centromeres are transcribed and that this transcriptional activity can occur during mitosis [7-9], adding an extra level of complexity to our models of centromere and kinetochore regulation.…”