Cytogenetic stability of chicken T‐cell line transformed with Marek's disease virus: atomic force microscope, a new tool for investigation

Abstract

The Marek's disease virus (MDV) integration may induce a novel organization of chromatin architecture with a modified genetic expression. In our opinion it is worthwhile trying to relate cytogenetic stability to functional modifications. Recently, atomic force microscopy technique was applied to study the structure of chromosomes at a nanoscale level. This high resolution allows to investigate the different structure of chromatin in order to study cytogenetic stability and chromosome aberrations due to MDV insertion. In this paper data are presented indicating a duplication [78,WZ,dup(1p)(p22-p23)] and a deletion [78,WZ cht del(3)(q2.10)] of Chromosomes 1 and 3 relatively. Relationships between GTG (G-bands by Trypsin using Giemsa) bands and the topography of chromosomes are also discussed, naming them Topographic Banding. The architecture of chromosomes observed by AFM can be related to the data obtained with classic banding techniques thus overcoming the optical resolution limits. The presence of chromatin bridges between sister chromatids at most of the heterochromatic regions is also evidenced. Besides, we present different studies of the longitudinal and transversal symmetry of the hetero and euchromatic regions to clearly demonstrate a different underlying architecture of these regions. It is indeed evident that the heterochromatic bands are more symmetrical than euchromatic bands.

Atomic Force Microscopy in Detection of Viruses

“…Di Bucchianico et al investigated the different structure of chromatin in chromosome aberrations due to MDV insertion. They found a duplication [78,WZ,dup(1p)(p22-p23)] and a deletion [78,WZ cht del(3)(q2.10)] of chromosomes 1 and 3 (Di Bucchianico, Giardi et al 2010). The architecture of chromosomes observed by AFM can be related to the data obtained with classic banding techniques.…”

“…Also, evidence the presence of chromatin bridges between sisters and deletions of chromatid regions. The deletions of the two chromatids have a size of 100 and 50 nm, respectively (Di Bucchianico, Giardi et al 2011). …”

Atomic Force Microscope nanolithography on chromosomes to generate single-cell genetic probes

“…AFM imaging allows the identification of a pattern of banding as well as a fibrous structure (with diameter of around 50 nm). Structural protrusions along the chromosome correspond to the "G-positive" bands thus making the region to be dissected recognizable with a topographical banding [10]. The band (1p)(p22-p23), that results duplicated in one of the two homologous chromosomes, has been selected in the unduplicated homologue to be dissected in order to produce a probe for the FISH.…”

“…Cytogenetic analysis of MDCC-MSB1, a chicken T-cell line transformed with Marek's Disease Virus (MDV), has been performed with both classical methods and AFM demonstrating a duplication of the short arm of chromosome 1, (1p)(p22-p23) [10]. …”

Cytogenetic analysis of quinoa chromosomes using nanoscale imaging and spectroscopy techniques

“…Recently, the fluorescence in situ hybridization (FISH) technique has been commonly adopted [4] as a sensitive tool for determining aberrations on chromosomes. A major drawback of the FISH technique is that the fluorescence intensity only roughly reflects the local density of packed DNA inside chromosomes and does not correspond to the topographic height [5,6]. In addition, higher cost, staining, and the long analysis protocol make the FISH technique cumbersome, expensive, less accurate, and manual.…”