The underlying structure of the subtelomeric region detected by microphotometrical scanning and chromosome graphic image analysis

Drets, Máximo E.; Mendizábal, Marcos

doi:10.1016/s0027-5107(98)00089-x

Mutation Research/Fundamental and Molecular Mechanisms of Mutag

1998

DOI: 10.1016/s0027-5107(98)00089-x

|View full text |Cite

The underlying structure of the subtelomeric region detected by microphotometrical scanning and chromosome graphic image analysis

Máximo E. Drets

Marcos Mendizábal

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...

Citation Types

Supporting

Mentioning

Contrasting

Year Published

2002

2010

Publication Types

Select...

Article6

Relationship

Self Cite1

Independent5

Authors

Journals

Cited by 7 publications

(1 citation statement)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alternatively, the distribution of HD chromatin could be classified in a simplified way as symmetrical (pattern type I) or asymmetrical (patterns type II and III). These patterns were confirmed by scanning T-banded endoreduplicated CHO chromosomes in which the same interchromatid distribution of HD chromatin appeared in both sister chromosomes (Drets and Mendizábal, 1998). Nevertheless, quantitative computerized microdensitometrical analyses on the distribution of HD chromatin at opposite ends of T-banded chromosomes have not yet been reported.…”

mentioning

confidence: 87%

Non-random distribution of high density chromatin detected at opposite ends of T-banded human metaphase chromosomes

Santiñaque

Drets

2007

Genet. Mol. Biol.

Self Cite

View full text Add to dashboard Cite

Previous research using microdensitometric scanning and computer graphic image analysis showed that T-banded segments of human metaphase chromosomes usually exhibit an asymmetrical distribution of high density (HD) chromatin between sister chromatids. Here, we employed the same methods to analyze HD chromatin distribution at opposite ends of T-banded human lymphocyte chromosomes. This study revealed that in most chromosomes with an asymmetrical distribution of HD chromatin at both ends, the highest densities of each arm were located in opposite chromatids. The frequency of this configuration was 0.792 per chromosome, indicating that the highest chromatin densities of the terminal segments of T-banded human chromosomes were non-randomly distributed at opposite chromosome arms. The possible relationship of this observation to the mode of replication of the terminal chromosome region is briefly discussed.Key words: human chromosomes, T-banding, chromatin structure, telomere, microdensitometry. It is well known that the usual banding procedures (C-, G-, R-and T-) reveal the underlying structure and composition of DNA and associated proteins in mitotic chromosomes (Therman and Susman, 1993). The specialized chromatin structure and the GC-richness of the telomeric/ subtelomeric DNA (de Lange, 2005;Riethman et al., 2004) confer high resistance to heat denaturation to the terminal regions of metaphase chromosomes which results in selective staining after T-banding (Dutrillaux, 1973). T-banding is a modification of R-banding procedure and is obtained through the incubation of chromosomes in a buffer at a high temperature followed by Giemsa staining. This procedure results in T-bands as darkly stained segments in lightly stained chromosomes. Scanning electron microscopy showed that T-bands are areas of highly aggregated chromatin fibres (Jack et al., 1986;Allen et al., 1988).Microdensitometric scanning and computer graphic image analysis of high-resolution microphotographs of Tbanded segments of human and Chinese Hamster Ovary (CHO) chromosomes allowed the detection of a differential distribution of HD sub-telomeric chromatin between sister chromatids. The different patterns observed were arbitrarily classified in three kinds of HD chromatin distribution, namely: Type I, HD segments were of similar size in both sister chromatids; Type II, HD predominated in one of the chromatids; and Type III, HD was detected in only one chromatid (Drets et al., 1992). Alternatively, the distribution of HD chromatin could be classified in a simplified way as symmetrical (pattern type I) or asymmetrical (patterns type II and III). These patterns were confirmed by scanning T-banded endoreduplicated CHO chromosomes in which the same interchromatid distribution of HD chromatin appeared in both sister chromosomes (Drets and Mendizábal, 1998). Nevertheless, quantitative computerized microdensitometrical analyses on the distribution of HD chromatin at opposite ends of T-banded chromosomes have not yet been reported. Therefore, we perform...

show abstract

mentioning

confidence: 87%

Non-random distribution of high density chromatin detected at opposite ends of T-banded human metaphase chromosomes

Santiñaque

Drets

2007

Genet. Mol. Biol.

Self Cite

View full text Add to dashboard Cite

show abstract

Chromosomal aberrations: formation, identification and distribution

Obe

Pfeiffer

Savage

et al. 2002

Mutation Research/Fundamental and Molecular Mechanisms of Mutag

262

148

View full text Add to dashboard Cite

Untitled

Olovnikov

2003

Biochemistry (Moscow)

View full text Add to dashboard Cite

The redusome hypothesis of aging and the control of biological time in individual development is proposed. Redusomes are hypothetical perichromosomal particles arising in differentiation events during morphogenesis of an organism. The linear molecule of DNA covered with proteins in the redusome is assumed to be a copy of a segment of chromosomal DNA. Redusomes are located mainly in subtelomeric regions of chromosomes. The redusome does not leave the body of a chromosome even in the course of cellular divisions, being kept in its chromosomal nest. Like telomeric DNA, redusome linear DNA is shortened step by step. Thus, tiny redusomes progressively decrease in size; it is from here their name originates. Together with loss of the length of DNA in a redusome, the number of different genes contained in it also decreases. Shortening of the redusomal DNA molecules (and, coupled to it, changes of the sets of genes in redusomes) is responsible for age-dependent shifts in the level of expression of different chromosomal genes. Owing to this, redusome DNA shortening serves as a key means of measuring biological time in individual development. The main part of DNA of most redusomes is postulated to be occupied by noncoding genes. Low-molecular-weight RNAs (micro RNAs and fountain RNAs, or fRNAs) are assumed to be transcribed from them. These RNAs are involved in regulation of various chromatin repackings that are specific to certain differentiations, while others modulate the levels of expression of chromosomal genes. Hypothetical fountain RNAs can quantitatively regulate the expression levels of chromosomal genes, forming specific complexes with fions. Fions are suggested to be specific sites of a chromosomal DNA which are complementary to different fRNAs. Fions reside in the vicinity of usual chromosomal genes. A complex of the fRNA-fion, specifically interacting with a closed gate of the corresponding ion channel of the internal nuclear membrane, initiates the opening of the gate for a very short time, thus organizing activity of an ion fountain which appears to be automatically aimed at the chromosomal gene nearest to the fion involved. The ion fountain creates, depending on specificity of matching fRNA, fion, and ion channel, a distinctive ionic environment near certain structural genes. Ion fountains exert their action on the configuration of corresponding segments of chromatin and on the transcriptional efficiency of chromosomal genes in a topographically specific manner. Hence, the fountain system of the nucleus is able to regulate the quantitative traits both of cells and organism; it can control dominance of alleles and plays a role in individual development. Significant and escalating truncation of the redusome DNA causes cell aging due to an arising and increasing deficit of fRNAs and, for this reason, the lack of required ions near certain structural genes. Progressive shortening of DNA of redusomes is proposed to result in cellular aging because of a constantly growing shortage of low-molecular-weight RNAs tra...

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

hi@scite.ai

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

The underlying structure of the subtelomeric region detected by microphotometrical scanning and chromosome graphic image analysis

Cited by 7 publications

References 8 publications

Non-random distribution of high density chromatin detected at opposite ends of T-banded human metaphase chromosomes

Non-random distribution of high density chromatin detected at opposite ends of T-banded human metaphase chromosomes

Chromosomal aberrations: formation, identification and distribution

Untitled

Contact Info

Product

Resources

About