Unique Aspects of rRNA Biogenesis in Trypanosomatids

The Nucleolar DExD/H Protein Hel66 is Involved in Ribosome Biogenesis in Trypanosoma Brucei

“…Trypanosomes have about 51 DExD/H helicases 33,34,37 , and many localise either in nucleolar (19) or nucleoplasmic (9) regions 39 , indicating that the majority of this protein family may be involved in ribosome processing. A total of 17 of these DExD/H RNA helicases mostly those with nucleolar localisation, have been assigned to yeast homologues with known functions in ribosome biogenesis [13][14][15] . These 17 proteins were also co-puri ed with at least one of four proteins involved in ribosome processing in Leishmania tarentolae 15 .…”

“…Most strikingly, the 25/28S rRNA of trypanosomes is processed into six further fragments, two larger ones and four small ones [16][17][18][19] . Trypanosome homologues to proteins involved in ribosome biogenesis in yeast were identi ed by homology 14 and more recently also by purifying early, middle and late processomes of the ribosomal subunits from the related Kinetoplastida Leishmania tarentolae 15 . These include several homologues to DEAD box RNA helicases.…”

The nucleolar DExD/H protein Hel66 is involved in ribosome biogenesis in Trypanosoma brucei

“…Trypanosomes have about 51 DExD/H helicases 33,34,37 , and many localise either in nucleolar (19) or nucleoplasmic (9) regions 39 , indicating that the majority of this protein family may be involved in ribosome processing. A total of 17 of these DExD/H RNA helicases mostly those with nucleolar localisation, have been assigned to yeast homologues with known functions in ribosome biogenesis [13][14][15] . These 17 proteins were also co-purified with at least one of four proteins involved in ribosome processing in Leishmania tarentolae 15 .…”

“…The parasite belongs to the Discoba clade and is highly divergent from the opisthokonts which belong to one of the major eukaryotic kingdoms 12 . T. brucei therefore separated from the major eukaryotic lineage early in evolution and possesses several unique features in its biology including its rRNA metabolism [13][14][15] . Most strikingly, the 25/28S rRNA of trypanosomes is processed into six further fragments, two larger ones and four small ones [16][17][18][19] .…”

“…Most strikingly, the 25/28S rRNA of trypanosomes is processed into six further fragments, two larger ones and four small ones [16][17][18][19] . Trypanosome homologues to proteins involved in ribosome biogenesis in yeast were identified by homology 14 and more recently also by purifying early, middle and late processomes of the ribosomal subunits from the related Kinetoplastida Leishmania tarentolae 15 . These include several homologues to DEAD box RNA helicases.…”