Human ring chromosomes and small supernumerary marker chromosomes-do they have telomeres?
Ring chromosomes and small supernumerary marker chromosomes (sSMC) are enigmatic types of derivative chromosomes, in which the telomeres are thought to play a crucial role in their formation and stabilization. Considering that there are only a few studies that evaluate the presence of telomeric sequences in ring chromosomes and on sSMC, here, we analyzed 14 ring chromosomes and 29 sSMC for the presence of telomeric sequences through fluorescence in situ hybridization (FISH). The results showed that ring chromosomes can actually fall into two groups: the ones with or without telomeres. Additionally, telomeric signals were detectable at both ends of centric and neocentric sSMC with inverted duplication shape, as well as in complex sSMC. Apart from that, generally both ring- and centric minute-shaped sSMC did not present telomeric sequences neither detectable by FISH nor by a second protein-directed immunohistochemical approach. However, the fact that telomeres are absent does not automatically mean that the sSMC has a ring shape, as often deduced in the previous literature. Overall, the results obtained by FISH studies directed against telomeres need to be checked carefully by other approaches.
Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Kollegiengasse 10, 07743, Jena, Germany.
Roberta Santos
RS
Guilherme
Elisabeth
E
Klein
Claudia
C
Venner
Ahmed B
AB
Hamid
Samarth
S
Bhatt
Maria Isabel
MI
Melaragno
Marianne
M
Volleth
Anna
A
Polityko
Anna
A
Kulpanovich
Nadezda
N
Kosyakova
Thomas
T
Liehr
D002869:Chromosome Aberrations; D005819:Genetic Markers; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D012303:Ring Chromosomes; D017422:Sequence Analysis, DNA; D016615:Telomere / Q000235:genetics*
D005819:Genetic Markers