Identification, phylogeny and expression analysis of NAP-family histone chaperones in maize (Zea mays)

In eukaryotes cells, genomic DNA in combination with histone proteins is formed the chromatin. Histone chaperones affect the gene transcription via altering in DNA accessibility. In contrast to their animal and yeast counterparts, not much is known about plant histone chaperones. Nucleosome assembly protein (NAP) family histone chaperones are conserved throughout eukaryotic genomics. NAP is an integral component in the establishment, maintenance, and dynamics of eukaryotic chromatin. They transfer histones into the nucleus, assemble nucleosomes, and promote chromatin fluidity, thereby, affecting the transcription of many genes. In this study, by applying some bioinformatics analysis approaches, six putative NAP genes (ZmNAPL1–ZmNAPL6) were identified in maize (Zea mays) using the released maize genomic sequences. Phylogenetic analysis showed that these ZmNAPLs are classified into two subgroups as found in Arabidopsis and rice. Moreover, it was found that maize NAPL proteins are more closely related to rice. The ZmNAPL genes contained three to eleven introns and were distributed across 5 out of 20 chromosomes in maize. Microarray-based expression analysis of ZmNAPLs showed that there is a tight transcriptional regulation on ZmNAPL genes during the plant development in maize suggesting that they may play a role in genetic reprogramming in association with the developmental process. This study is the first report about NAPL gene family in maize and obtained results provide basic information for future research on the functions of NAPL genes in maize.