Variability of Human rDNA

Abstract

In human cells, ribosomal DNA (rDNA) is arranged in ten clusters of multiple tandem repeats. Each repeat is usually described as consisting of two parts: the 13 kb long ribosomal part, containing three genes coding for 18S, 5.8S and 28S RNAs of the ribosomal particles, and the 30 kb long intergenic spacer (IGS). However, this standard scheme is, amazingly, often altered as a result of the peculiar instability of the locus, so that the sequence of each repeat and the number of the repeats in each cluster are highly variable. In the present review, we discuss the causes and types of human rDNA instability, the methods of its detection, its distribution within the locus, the ways in which it is prevented or reversed, and its biological significance. The data of the literature suggest that the variability of the rDNA is not only a potential cause of pathology, but also an important, though still poorly understood, aspect of the normal cell physiology.

The role of gut mycobiome in health and diseases

“… 28 Because ITS regions show not only fewer number of ribosomal gene copies but also less relative abundance of variants and breakpoints in various regions per unit in human rDNA. 84 A preview results nonetheless support that the result of 18s rDNA PCR, which compares with one of ITS PCR, shows significant diagnostic and accurate identification of fungal pathogens in clinical sample from fresh biopsies and punctate and deep wound secretions. 85 Compared with target sequence, metagenomics reads might be decreased biases from primer choices and increased community taxonomic characterization providing information of gene composition and the function.…”

Циркулирующая Внеклеточная ДНК Здоровых Людей Значительно Отличается От Клеточной ДНК По Относительному Содержанию GC- И Ат- Богатых Тандемных Повторов

“…Протокол количественного анализа двух повторов в составе ДНК человека описан ранее [3,4]. Из кубитальной вены забирали 5 мл крови в пробирки с ЭДТА.…”

“…Повтор локализован в р-районах акроцентрических хромосом. Геном человека содержит от 200 до 700 копий рДНК [3]. АТ-богатый повтор (62 % АТ-пар) -фрагмент (длина 1770 пар нуклеотидов) сателлита III (SatIII) локализован в районе 1q12 первой хромосомы.…”

RNA Polymerase I Is Uniquely Vulnerable to the Small-Molecule Inhibitor BMH-21

“…Pol I transcription of the ribosomal DNA (rDNA) is tightly regulated and proportional to cellular growth rate [ 12 , 13 ]. In human cells, Pol I synthesizes the 47 S pre-ribosomal RNA (rRNA) from clusters of ~400 tandem repeats found on chromosomes 13, 14, 15, 21, and 22 [ 14 , 15 ]. The 47 S pre-rRNA is co- and post-transcriptionally processed to form the mature 18 S, 5.8 S, and 28 S rRNAs [ 16 ].…”