Telomeric location of Giardia rDNA genes.

Telomeric location of Giardia rDNA genes.

Giardia lamblia telomeres have been isolated from a library enriched for repaired chromosome ends by (i) screening with a Plasmodium falciparum telomere and (ii) differential hybridization with Bal 31-digested and total G. lamblia DNA. Analysis of three clones isolated by this strategy has identified multiple tandem repeats of the 5-mer TAGGG. An oligonucleotide containing these repeats recogni...

Trf4 targets ncRNAs from telomeric and rDNA spacer regions and functions in rDNA copy number control

Trf4 is the poly(A) polymerase component of TRAMP4, which stimulates nuclear RNA degradation by the exosome. We report that in Saccharomyces cerevisiae strains lacking Trf4, cryptic transcripts are detected from regions of repressed chromatin at telomeres and the rDNA intergenic spacer region (IGS1-R), and at CEN3. Degradation of the IGS1-R transcript was reduced in strains lacking TRAMP compon...

Explorer Trf 4 targets ncRNAs from telomeric and rDNA spacer regions and functions in rDNA copy number control

Split Genes: Another Surprise from Giardia

Some genes in the candidate early-branching eukaryote Giardia lamblia occur in separate pieces, transcribed from non-contiguous chromosomal locations. The pre-mRNAs from the separate pieces apparently find each other by regions of complementarity and are subsequently spliced together by the spliceosome. Could genes in pieces, transcribed into separate pre-mRNAs, have been an early feature of sp...

Localization of 45S rDNA and telomeric sites on holocentric chromosomes of Rhynchospora tenuis Link (Cyperaceae)

Rhynchospora tenuis Link (Cyperaceae) is a weed widely distributed in Brazil that presents a small number of holocentric chromosomes (2n = 4) with some autopolyploid populations (2n = 8). The haploid number n = 2 is considered as a derivative of the base number x = 5. 45S rDNA probes and telomeric DNA were hybridized in both chromosome races of R. tenuis, looking for indications of chromosome f...