Paper Title
Identification of Nucleolin-Like 2 as a Stress-Inducible Gene

Abstract
Nucleolin usually exists in vertebrate in one copy, such as in human, in contrast, plants contain two or more genes (different but conserved structurally) that encode nucleolin-like proteins. ). Arabidopsis thaliana, that is an ancient duplicated plant (Blanc et al., 2000) contains two nucleolin like protein genes which are found in duplicated region of DNA on chromosome 1 (AtNUC1) and chromosome 3 (AtNUC2). Over time, many duplicated genes are lost. However, those that are retained might gain new functions (neofunctionalization) and/or show specific expression patterns. AtNUC2 promoter contains elements related to stress including HSE, DRE, ABRE and MYCATRD22 and moreover W box and CCAAT-box which are found in AtNUC2 and AtNUC1 gene promoters. Here, we demonstrate that AtNUC2 gene expression is induced by heat shock and salicylic acid. Then, we validate the function of HSE in controlling AtNUC2 gene expression in both heat shock and normal conditions. The Cis-acting elements which are found in AtNUC2 promoter, in particular the HSE, could be DNA binding sites for one or more trans-acting factors, which could regulate gene expression under stress or normal conditions. Finally, AtNUC2 promoter activity was also detected in flowers: mainly in tapetum and/or parenchyma cells. Also, cell death program might occur in tapetum and parenchyma cells surrounding pollen grains to allow them to spray throughout pollen sac. Thus, it is possible that, AtNUC2 gene expression is correlated with cell death program, although the molecular function remains to be determined. Keywords - Nucleolin Like Protein, HSE, DRE, ABRE, MYCATRD22 and W box, Cell Death Program.