A direct interaction between the Utp6 half-a-tetratricopeptide repeat domain and a specific peptide in Utp21 is essential for efficient pre-rRNA processing.
The small subunit (SSU) processome is a ribosome biogenesis intermediate that assembles from its subcomplexes onto the pre-18S rRNA with yet unknown order and structure. Here, we investigate the architecture of the UtpB subcomplex of the SSU processome, focusing on the interaction between the half-a-tetratricopeptide repeat (HAT) domain of Utp6 and a specific peptide in Utp21. We present a comprehensive map of the interactions within the UtpB subcomplex and further show that the N-terminal domain of Utp6 interacts with Utp18 while the HAT domain interacts with Utp21. Using a panel of point and deletion mutants of Utp6, we show that an intact HAT domain is essential for efficient pre-rRNA processing and cell growth. Further investigation of the Utp6-Utp21 interaction using both genetic and biophysical methods shows that the HAT domain binds a specific peptide ligand in Utp21, the first example of a HAT domain peptide ligand, with a dissociation constant of 10 muM.
Champion
Erica A
EA
Department of Genetics, Yale University School of Medicine, New Haven, CT 06520-8040, USA.
Lane
Bennett H
BH
Jackrel
Meredith E
ME
Regan
Lynne
L
Baserga
Susan J
SJ
D000595:Amino Acid Sequence; D008024:Ligands; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000378:metabolism; D012322:RNA Precursors / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D020449:Repetitive Sequences, Amino Acid; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*
D008024:Ligands; D009687:Nuclear Proteins; D010455:Peptides; D021122:Protein Subunits; D012322:RNA Precursors; D029701:Saccharomyces cerevisiae Proteins; C531337:Utp21 protein, S cerevisiae; C532747:Utp6 protein, S cerevisiae