Characterization of a cDNA encoding a novel plant poly(A) polymerase

Jaydip Das Gupta, Qing Shun Li, A. Brian Thomson, Arthur G. Hunt

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


We have isolated cDNA clones encoding a novel factor (PAP-I) that is a component of a multi-subunit poly(A) polymerase from pea seedlings. The encoded protein, when isolated from appropriately engineered Escherichia coli, was active as a poly(A) polymerase, either with an associated RNA binding cofactor (PAP-III) or with free poly(A) as an RNA substrate. The latter observation indicates that PAP-I is in fact a poly(A) polymerase. PAP-I bore a striking resemblance to an as yet uncharacterized cyanobacterial protein. This observation suggested a possible chloroplast localization for PAP-I. This hypothesis was tested and found to be substantiated; immunoblot analysis identified PAP-I in chloroplast but not nuclear extracts. Our results suggest that PAP-I is a component of the machinery that adds poly(A) to chloroplast RNAs.

Original languageEnglish
Pages (from-to)729-734
Number of pages6
JournalPlant Molecular Biology
Issue number4
StatePublished - Jul 1998

Bibliographical note

Funding Information:
We are grateful to Carol Von Lanken for technical assistance, and to Santanu Das Gupta and Gautam Sen for assistance in preparing antibodies. We thank Dr A.S.N. Reddy for the gift of the anti-U1 antiserum and Dr R. Houtz for anti-rbcL antibodies. This work was supported by a grant (95-37301-2041) from the USDA NRI Competitive Grant Program.


  • Chloroplast RNA processing
  • Poly(A) polymerase

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Genetics
  • Plant Science


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