Chromosomal mapping and nucleotide sequence of two tandem repeats of Atlantic salmon 5S rDNA

Abstract

Atlantic salmon 5S ribosomal DNA (5S rDNA) was amplified by the polymerase chain reaction, using as primers conserved sequences from the coding region of rainbow trout 5S rRNA. Two amplified products of different molecular weights were obtained, cloned, and sequenced, revealing them to be tandemly arranged. The nucleotide sequences differed between the two clones in the length of the nontranscribed spacer (NTS) and in three nucleotides of the coding sequence. By means of fluorescence in situ hybridization the 5S rDNA was chromosomally located in the heterochromatic arm of the pair bearing the satellite, adjacent to the major ribosomal DNA locus (rDNA).

FISH mapping of 18S-28S and 5S ribosomal DNA, (GATA)n and (TTAGGG)n telomeric repeats in the periwinkle Melarhaphe neritoides (Prosobranchia, Gastropoda, Caenogastropoda)

“…In fact, among vertebrates, an adjacent disposition between NORs and telomeres is reported to be an unusual finding (see Liu and Fredga, 1999) and a co-localization of 18S-28S and 5S rDNAs is not considered the rule, but rather the exception (Sola et al, 2000;Mandrioli et al, 2000). For example, in fish, a co-localization of repeated units of ribosomal DNAs has been described only in four out of 20 species so far analyzed (Pendás et al, 1994;Morán et al, 1996;Mandrioli et al, 2000).…”

Mapping of ribosomal genes and chromosomal markers in three species of the genus Serrasalmus (Characidae, Serrasalminae) from the Amazon basin

“…The 18S rDNA probe was obtained by PCR from the DNA of the fish Prochilodus argenteus (Hatanaka and Galetti, 2004), using the primers NS1 (5'-GTAGTCATATGCTTGTCT C-3') and NS8 (5'-TCCGCAGGTTCACCTACGGA-3'), according to White et al (1990). The 5S rDNA probe was obtained from the fish Leporinus obtusidens (Martins and Galetti, 1999), using the primers A (5'-TACGCCCGATC TCGTCCGATC-3') and B (5'-CAGGCTGGTATGGCC GTAAGC-3'), according to Pendás et al (1994). The probes were labeled by nick translation (BioNick Labeling System -Invitrogen) following the manufacturer's specifications.…”

Interindividual size heteromorphism of NOR and chromosomal location of 5S rRNA genes in Iheringichthys labrosus

“…In the family Pimelodidae, the 18S rDNA probe has been utilized in Zungaro zungaro (Swarça et al, 2001a), Pinirampus pirinampu (Swarça et al, 2001b) and some species of Pimelodus (Souza et al, 2004), among others. The 5S rDNA genes consist of highly conserved sequences of 120 base pairs (Pendás et al, 1994) and have been studied in fish such as Prochilodus lineatus (Jesus and Moreira-Filho, 2003), Astyanax scabripinnis (Marco-Ferro et al, 2001), some species of Parodon (Vicente et al, 2001) and Hoplias (Born and Bertollo, 2000). This work aimed to analyse the NORs of Iheringichthys labrosus (Siluriformes, Pimelodidae), using different treatments: AgNO 3 , CMA 3 and FISH with the 18S rDNA probe, and to determine the location of 5S rDNA genes.…”