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.

Repetitive DNA is a major organizational component of eukaryotic genomes, being intrinsically related with their architecture and evolution. Tandemly repeated satellite DNAs (satDNAs) can be found clustered in specific heterochromatin-rich chromosomal regions, building vital structures like functional centromeres and also dispersed within euchromatin. Interestingly, despite their association to critical chromosomal structures, satDNAs are widely variable among species due to their high turnover rates. This dynamic behavior has been associated with genome plasticity and chromosome rearrangements, leading to the reshaping of genomes. Here we present the current knowledge regarding satDNAs in the light of new genomic technologies, and the challenges in the study of these sequences. Furthermore, we discuss how these sequences, together with other repeats, influence genome architecture, impacting its evolution and association with disease.

Repetitive satellite DNA (satDNA) sequences are abundant in eukaryote genomes, with a structural and functional role in centromeric function. We analyzed the nucleotide sequence and chromosomal location of the five known cattle ( Bos taurus ) satDNA families in seven species from the tribe Tragelaphini (Bovinae subfamily). One of the families ( SAT1.723 ) was present at the chromosomes’ centromeres of the Tragelaphini species, as well in two more distantly related bovid species, Ovis aries and Capra hircus . Analysis of the interaction of SAT1.723 with centromeric proteins revealed that this satDNA sequence is involved in the centromeric activity in all the species analyzed and that it is preserved for at least 15–20 Myr across Bovidae species. The satDNA sequence similarity among the analyzed species reflected different stages of homogeneity/heterogeneity, revealing the evolutionary history of each satDNA family. The SAT1.723 monomer-flanking regions showed the presence of transposable elements, explaining the extensive shuffling of this satDNA between different genomic regions.