The Differential Expression Level Of HAT And HDAC In Different Cotton Species

Epigenetic regulation is a major aspect of gene control by which heritable changes in gene expreesion occured without an alteration in DNA sequence. As gene mutation, epigenetic modification can cause the structural and functional changes of cells, tissues, organs and whole body, and even lead to diseases. The gene transcription was influenced by the histone modifying enzyme complexes with the covalent modification of histone.The known modifications contains methylation, acetylation, phosphorylation, ubiquitination, ADP ribosylation etc.. In particular, acetylation modification play an important role in chromatin structure changes and transcriptional regulation. The level of histone acetylation is regulated by the histone acetyltransferase (HATS) with the acetylation modification of core histone. This further control gene transcription and gene expression regulation which resulted in gene activation or silence. Normally, high level of histone acetylation lead to gene activation, and the low histone acetylation often associated with inhibition of gene activity.In this paper, the expreesion differences of histone acetyltransferase (HATs) and histone deacetylase(HDACs) among different cotton species and at different growing periods in the same species were studied by the techiniques of RT-PCR and sequence analysis. The materials included four types of cultivated species such as G. herbaceum, G. arboreum, G. Barbadense and G. hirsutum. The main conclusions are as follow:1. the level of expression of HATs and HDACs were the same in the diploid cotton or tetraploid cotton at the same stage.2. The expression level of HAT 1 in tetraploid cotton at seedling stage, flowering stage and boll opening stage was greater than that in the diploid cotton, while the HAT2 is opposite. The expression levels of HDAC1 and HDAC2 were the same at flowering stage, boll opening stage and seedling stage. This indicated that the expression level of HAT 1 and HAT2 were related with ploidy of cotton. Expression level of HAT 1 is greater in tetraploid cotton, but HAT2 is less. And HDAC1, HDAC2 are not related with chromosomal ploidy.3. The HAT1 gene expression levels at seedling stage was the same as that at flowering stage in the tetraploid cotton. However, the expression level was higher at the seedling stage, and decreased gradually at the flowering stage in diploid cotton. HAT2 gene expression at seeding stage was higher than that at the flowering stage in both diploid cottons and tetraploid cottons. But the expression of the HDAC1 and HDAC2 genes at seeding stage was less than that at flowering stage in both diploid cottons and tetraploid cottons. This shows that histone deacetylase genes (HDAC1, HDAC2) was related to growth proces with a low expression at early growth stage and high expression at flowering period. However, higher expression of HAT2 in early growth stage with a lower expression during flowering.period was also observed in the cottons.