Poster: Regulation of gene expression

Abs # 778: Cloning and characterization of the Arabidopsis Thaliana poly (A) polymerase gene family

Presenter:	Meeks, Lisa R., lrmeek1@uky.edu
Authors	Meeks, Lisa R. (A)   Addepalli, Balasubrahmanyam  (A)   Forbes, Kevin P. (A)   Hunt, Arthur G (A)
Affiliations:	(A): University of Kentucky, Department of Agronomy

Mature, functional messenger RNAs (mRNAs) arise from nascent RNAs that have undergone extensive processing. One of these processes is the addition of a 3’ poly (A) tail. This step involves an endonucleolytic cleavage at a cleavage signal then subsequent addition of a string of adenosine residues 3’ of the cleavage site. Our lab has focused on the 3’ end processing factors involved in plant poly (A) tail formation. To better understand how the poly (A) tail is added to nascent mRNAs, I have been characterizing the poly (A) polymerase (PAP) genes found in Arabidopsis thaliana. PAP is the enzyme responsible for the addition of the poly (A) tail during mature mRNA formation. Arabidopsis has four PAP genes located on chromosomes I, II, III, and IV. Alignment of the PAP proteins show that enzymes arising from chromosomes I, II, and IV appear to be closely related, but the chromosome III gene, when compared to the other three PAPs, is truncated and is missing one or both of the nuclear localization signals found in the other PAPs. Also, the three similar genes have alternative spicing around intron 6, which is not seen in PAP III. The structure, expression, and alternative splicing of these four PAP genes will be addressed as well as the localization of the PAP proteins.