The very complex life cycle and extreme diversity of insect life forms require a carefully regulated network of biological processes to switch on and off the right genes at the right time. Chromatin condensation is an important regulatory mechanism of gene silencing as well as gene activation for the hundreds of functional protein genes harbored in heterochromatic regions of different insect species. Being the major heterochromatin constituents, satellite DNAs (satDNAs) serve important roles in heterochromatin regulation in insects in general. Their expression occurs in all developmental stages, being the highest during embryogenesis. satDNA transcripts range from small RNAs, corresponding in size to siRNAs, and piwiRNAs, to large, a few kb long RNAs. The long transcripts are preferentially nonpolyadenylated and remain in the nucleus. The actively regulated expression of satDNAs by cis or trans elements as well as by environmental stress, rather than constitutive transcription, speaks in favor of their involvement in differentiation, development, and environmental response.
Satellite DNAs (satDNAs) are tandemly repeated sequences that make up a significant portion of almost all eukaryotic genomes. Although satDNAs have been shown to play an important role in genome organization and evolution, they are relatively poorly analyzed, even in model organisms. One of the main reasons for the current lack of in-depth studies on satDNAs is their underrepresentation in genome assemblies.
Tomato yellow leaf curl virus-Oman (TYLCV-OM), a variant of the Tomato yellow leaf curl virus-Iran (TYLCV-IR) strain, was identified in 2005 as the cause of tomato yellow leaf curl disease (TYLCD) in Oman and is associated with a betasatellite namely as Tomato leaf curl betasatellite (ToLCB). Surveys were carried out from three diverse Governorates of Oman to investigate the correlation between the betasatellite and the virus. The visual assessment and scoring of infected tomato plants in the field revealed that the association of betasatellite with the disease was highest in Sharqia at 77%, followed by Dakhlia at41% and lowest in Batinah at30% .
Skeletal muscle cells (myofibers) require multiple nuclei to support a cytoplasmic volume that is larger than other mononuclear cell types. It is dogmatic that mammalian resident myonuclei rely on stem cells (specifically satellite cells) for adding new DNA to muscle fibers to facilitate cytoplasmic expansion that occurs during muscle growth. In this review, we discuss the relationship between cell size and supporting genetic material.
Background And Aims: Genomic changes triggered by polyploidy, chromosomal rearrangements, and/ or environmental stress are among factors that affect the activity of mobile elements, particularly Long Terminal Repeats Retrotransposons (LTR-RTs) and DNA transposons. Because these elements can proliferate and move throughout host genomes, altering the genetic, epigenetic and nucleotypic landscape, they have been recognized as a relevant evolutionary force. Beaksedges (Rhynchospora) stand out for their wide cosmopolitan distribution, high diversity (~400 spp.
