Summary: Flower-preferential poly(A) binding (PAB) protein gene from rice
Jong-Jin Han, Gynheung An *
National Research Laboratory of Plant Functional Genomics, Molecular and Life Sciences, Pohang University of Science and Technology, Pohang 790-
784, South Korea
Received 17 January 2003; received in revised form 20 March 2003; accepted 21 March 2003
The Poly(A) binding (PAB) protein functions in posttranscriptional regulation by stabilizing mRNA and initiating translation.
Using sequence homology to Arabidopsis PAB genes, we have identified seven members (OsPAB1 through OsPAB7) of the PAB
gene family in rice. These can be divided into two groups based on sequence identity and expression pattern. The four genes in the
first clade*/OsPAB2, OsPAB4, OsPAB6, and OsPAB7 */share strong homology with AtPAB2, and are expressed in all the organs
that were examined here. The remaining three, OsPAB1, OsPAB3, and OsPAB5, show the specific expression pattern for flowering.
OsPAB1 is expressed throughout floral development, although its level decreases as the flowers mature. In contrast, expression of
OsPAB3 is evident in older flowers and developing seeds, while OsPAB5 transcript is present only in mature flowers. All the genes
in the second clade are expressed in carpels and stamens, but not in the paleae and lemmae of spikelets. In addition, we have
identified a T-DNA insertional line, in which the gus reporter gene is fused to OsPAB1 to produce the PAB1-GUS fusion protein.
In those experiments, GUS staining was strong in the ovaries and anthers, demonstrating that OsPAB1 is preferentially expressed in
the reproductive organs.
# 2003 Elsevier Science Ireland Ltd. All rights reserved.
Keywords: Flower; GUS; Poly(A) binding protein; Rice; T-DNA