Archaeal pre-mRNA splicing: a connection to hetero-oligomeric splicing endonuclease.
Eukaryotic Cbf5 is a protein subunit of the small nucleolar RNA-protein complex. Previously, we identified, in archaeal homologs of cbf5 of the crenarchaea, Aeropyrum pernix, Sulfolobus solfataricus, and Sulfolobus tokodaii, the first examples of introns of archaeal protein-coding genes. Here, we report the immunological detection of Cbf5 protein of S. tokodaii, the product of the spliced cbf5 mRNA. The hetero-oligomeric splicing endonuclease activity from recombinant S. tokodaii subunits cleaved at the exon-intron boundaries of cbf5 pre-mRNA fragments,suggesting that synthesis of full-length Cbf5 protein requires this activity. Database searches and PCR screens identified additional cbf5 introns in some, but not all sequenced crenarchaeal genomes. The predicted secondary structures of exon-intron boundaries of many of the newly identified intron-containing cbf5 pre-mRNAs contained relaxed forms of the bulge-helix-bulge motif similar to that of S. tokodaii. These observations are consistent with previous reports indicating that subunit composition of the splicing endonuclease contributes to substrate specificity.
Yoshinari
Shigeo
S
Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Itoh
Takashi
T
Hallam
Steven J
SJ
DeLong
Edward F
EF
Yokobori
Shin-ichi
S
Yamagishi
Akihiko
A
Oshima
Tairo
T
Kita
Kiyoshi
K
Watanabe
Yoh-ichi
Y
D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D004722:Endoribonucleases / Q000378:metabolism*; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis / Q000235:genetics; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012326:RNA Splicing / Q000235:genetics*; D019642:RNA, Archaeal / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D016944:Sulfolobus / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics*
D019843:Archaeal Proteins; D012322:RNA Precursors; D019642:RNA, Archaeal; D004722:Endoribonucleases; C051012:splicing endonuclease