PMID- 18931488
OWN - NLM
STAT- MEDLINE
DCOM- 20081112
LR  - 20091103
IS  - 1424-859X (Electronic)
IS  - 1424-8581 (Linking)
VI  - 122
IP  - 1
DP  - 2008
TI  - Colocalization of repetitive DNAs and silencing of major rRNA genes. A case 
      report of the fish Astyanax janeiroensis.
PG  - 67-72
LID - 10.1159/000151318 [doi]
AB  - The heterochromatin composition and loca- tion in the genome of the fish Astyanax 
      janeiroensis was investigated using Chromomycin A(3) and DAPI fluorochromes and 
      fluorescence in situ hybridization (FISH) with 18S rDNA and As51 satellite DNA 
      probes, respectively. Distinct repetitive DNA classes were found, namely: (1) 
      C-positive centromeric/telomeric heterochromatin, (2) NOR-associated GC-rich 
      heterochromatin (18S(+)/GC(+)) and (3) As51(+)/18S(+) heterochromatin colocalized 
      on 14 distinct heterochromatic domains with attenuated fluorescence of DAPI 
      staining (As51(+)/18S(+)/DAPI attenuated signal). Besides these fourteen 
      associated repetitive DNAs, another eight sites with only 18S rDNA were also 
      found, comprising altogether 22 18S rDNA sites in the genome of the species under 
      study. Up to seven 18S rDNA sites were found to be active, i.e., were 
      characterized as positive after silver staining (Ag-NORs). It was noteworthy that 
      in all As51(+)/18S(+) domains the 18S rDNA were not found to be active sites due 
      to the silencing of these genes when associated with the As51 satellite DNA in 
      the same heterochromatic domain. The dispersion of the As51 sites in the genome 
      of the species is hypothesized to probably originate from a transposable element. 
      Several chromosomal and karyotype markers are similar between A. janeiroensis and 
      A. scabripinnis, indicating a close relationship between these species.
CI  - Copyright 2008 S. Karger AG, Basel.
FAU - Vicari, M R
AU  - Vicari MR
AD  - Universidade Estadual de Ponta Grossa, Depto. de Biologia Estrutural Molecular e 
      Genetica, Ponta Grossa, PR, Brazil. vicarimr@pq.cnpq.br
FAU - Artoni, R F
AU  - Artoni RF
FAU - Moreira-Filho, O
AU  - Moreira-Filho O
FAU - Bertollo, L A C
AU  - Bertollo LA
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20081014
PL  - Switzerland
TA  - Cytogenet Genome Res
JT  - Cytogenetic and genome research
JID - 101142708
RN  - 0 (DNA, Ribosomal)
RN  - 0 (Heterochromatin)
RN  - 9007-49-2 (DNA)
SB  - IM
MH  - Animals
MH  - Brazil
MH  - DNA/*genetics
MH  - DNA, Ribosomal/genetics
MH  - Female
MH  - Fishes/classification/*genetics
MH  - *Gene Silencing
MH  - *Genes, rRNA
MH  - Heterochromatin/genetics
MH  - In Situ Hybridization, Fluorescence
MH  - Karyotyping
MH  - Male
MH  - Repetitive Sequences, Nucleic Acid
EDAT- 2008/10/22 09:00
MHDA- 2008/11/13 09:00
CRDT- 2008/10/22 09:00
PHST- 2008/05/30 00:00 [accepted]
PHST- 2008/10/22 09:00 [pubmed]
PHST- 2008/11/13 09:00 [medline]
PHST- 2008/10/22 09:00 [entrez]
AID - 000151318 [pii]
AID - 10.1159/000151318 [doi]
PST - ppublish
SO  - Cytogenet Genome Res. 2008;122(1):67-72. doi: 10.1159/000151318. Epub 2008 Oct 
      14.