Molecular cloning and characterization of a novel isoform of the non-canonical poly(A) polymerase PAPD7

Koichi Ogami; Rihe Cho; Shin-ichi Hoshino

doi:10.1016/j.bbrc.2013.01.072

Molecular cloning and characterization of a novel isoform of the non-canonical poly(A) polymerase PAPD7

Biochem Biophys Res Commun. 2013 Mar 1;432(1):135-40. doi: 10.1016/j.bbrc.2013.01.072. Epub 2013 Jan 29.

Authors

Koichi Ogami¹, Rihe Cho, Shin-ichi Hoshino

Affiliation

¹ Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan.

PMID: 23376078
DOI: 10.1016/j.bbrc.2013.01.072

Abstract

Non-canonical poly(A) polymerases (ncPAPs) catalyze the addition of poly(A) tail to the 3' end of RNA to play pivotal roles in the regulation of gene expression and also in quality control. Here we identified a novel isoform of the 7th member of ncPAPs: PAPD7 (PAPD7 l), which contains 230 extra amino acids at the amino terminus of the previously identified PAPD7 (PAPD7 s). In sharp contrast to the inactive PAPD7 s, PAPD7 l showed robust nucleotidyl transferase activity when tethered to an RNA. A region required for the activity was localized to 187-219 aa, and this region was also required for the nuclear retention of PAPD7 l. Western blot analysis revealed that 94 kDa band (corresponding to PAPD7 l) but not 62 kDa band (corresponding to PAPD7 s) detected by PAPD7 antibody was specifically depleted by treatment with PAPD7 siRNA in both HeLa and U2OS cells. These results suggest that PAPD7 l is the major and active isoform of PAPD7 expressed in cells.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acid Sequence
Cell Nucleus / enzymology
Chromosomal Proteins, Non-Histone / chemistry
Chromosomal Proteins, Non-Histone / genetics
Chromosomal Proteins, Non-Histone / metabolism*
Cloning, Molecular
DNA-Directed DNA Polymerase / chemistry
DNA-Directed DNA Polymerase / genetics
DNA-Directed DNA Polymerase / metabolism*
DNA-Directed RNA Polymerases / chemistry
DNA-Directed RNA Polymerases / genetics
DNA-Directed RNA Polymerases / metabolism
Humans
Isoenzymes / chemistry
Isoenzymes / genetics
Isoenzymes / metabolism
Mitochondrial Proteins / chemistry
Mitochondrial Proteins / genetics
Mitochondrial Proteins / metabolism
Molecular Sequence Data
Mutation
Nuclear Localization Signals / chemistry
Nuclear Localization Signals / genetics
Nuclear Localization Signals / metabolism
Protein Structure, Tertiary
RNA Nucleotidyltransferases / chemistry
RNA Nucleotidyltransferases / genetics
RNA Nucleotidyltransferases / metabolism

Substances

Chromosomal Proteins, Non-Histone
Isoenzymes
Mitochondrial Proteins
Nuclear Localization Signals
RNA Nucleotidyltransferases
TENT4B protein, human
DNA-Directed RNA Polymerases
MTPAP protein, human
DNA-Directed DNA Polymerase
TENT4A protein, human