# Concept of natural genome reconstruction. Part 3. Analysis of changes in the amount of telomeric DNA in colony cells as a new amplified feature that arose during the processing of hematopoietic bone marrow stem cells

## TL;DR

This study explores how telomeric DNA increases in bone marrow stem cells after exposure to extracellular DNA, suggesting a new mechanism for genetic trait amplification.

## Contribution

The study introduces telomeric DNA amplification as a novel feature arising from extracellular DNA processing in hematopoietic stem cells.

## Key findings

- Telomeric DNA in colony cells significantly increased after treatment with double-stranded DNA.
- Telomeric DNA amplification is not linked to telomerase activity but may involve an extrachromosomal DNA template.
- Angiogenin treatment also increases telomeric DNA, but through a different mechanism than DNA treatment.

## Abstract

The induced “recombinogenic situation” in hematopoietic stem cells and the activation of the cell’s reparative systems create the basis for recombination events between fragments of extracellular double-stranded DNA delivered into the cell and chromosomal DNA or other forms of the reparative-recombination process. In mouse and rat model organisms as well as in human bone marrow cells, changes in the amount of telomeric DNA in hematopoietic stem cells were assessed as an indicator of repair and recombination events that have occurred. In all experiments performed, recombinant human angiogenin was used as a comparison factor. Dot blot hybridization showed that in the colony cells obtained from the bone marrow cells of the model organisms as well as from human bone marrow cells treated with a double-stranded DNA preparation, there was a significant increase in the amount of telomeric DNA. Amplification of telomeric DNA in colony cells is not associated with contamination of the original DNA preparation with which the bone marrow cells were treated. Treatment of bone marrow cells with DNA that does not carry telomeric sequences (AluI PCR fragment) does not lead to an increase in the amount of telomeric DNA in the cells of grown colonies. This suggests the participation in the amplification of telomeric DNA of an extrachromosomal DNA template carrying telomeric DNA. It has been established that treatment of bone marrow cells with angiogenin also leads to an increase in telomeric DNA in colony cells. A comparison of the type of colonies with the intensity of hybridization (i. e. the amount of telomeric DNA in the sample) suggests that the increase in the amount of detectable telomeric DNA following treatment with angiogenin and hDNAgr has a fundamentally different origin. Western blot analysis and real-time PCR revealed that the increase in the amount of telomeric DNA following treatment of bone marrow cells with a double-stranded DNA preparation does not correlate with the activity of endogenous/exogenous telomerase. For angiogenin, it has been shown that an increase in the amount of telomeric DNA may be the result of activation of endogenous telomerase activity. A principle has been developed for the amplification of a new genetic trait that came into hematopoietic stem cells with extracellular double-stranded DNA material and was fixed in the recipient genome or was transitively present in the cell as new genetic information.