The human 64-kDa polyadenylylation factor contains a ribonucleoprotein-type RNA binding domain and unusual auxiliary motifs.
Cleavage stimulation factor is one of the multiple factors required for 3'-end cleavage of mammalian pre-mRNAs. We have shown previously that this factor is composed of three subunits with estimated molecular masses of 77, 64, and 50 kDa and that the 64-kDa subunit can be UV-crosslinked to RNA in a polyadenylylation signal (AAUAAA)-dependent manner. We have now isolated cDNAs encoding the 64-kDa subunit of human cleavage stimulation factor. The 64-kDa subunit contains a ribonucleoprotein-type RNA binding domain in the N-terminal region and a repeat structure in the C-terminal region in which a pentapeptide sequence (consensus MEARA/G) is repeated 12 times and the formation of a long alpha-helix stabilized by salt bridges is predicted. An approximately 270-amino acid segment surrounding this repeat structure is highly enriched in proline and glycine residues (approximately 20% for each). When cloned 64-kDa subunit was expressed in Escherichia coli, an N-terminal fragment containing the RNA binding domain bound to RNAs in a polyadenylylation-signal-independent manner, suggesting that the RNA binding domain is directly involved in the binding of the 64-kDa subunit to pre-mRNAs.
Takagaki
Y
Y
Department of Biological Sciences, Columbia University, New York, NY 10027.
MacDonald
C C
CC
Shenk
T
T
Manley
J L
JL
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011061:Poly A / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D016601:RNA-Binding Proteins / Q000737:chemistry*; D012261:Ribonucleoproteins / Q000737:chemistry; D039221:mRNA Cleavage and Polyadenylation Factors
D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D039221:mRNA Cleavage and Polyadenylation Factors; D011061:Poly A; D004247:DNA