Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao, 266003, China; Department of Microbiology, University of Central Punjab, Lahore, Pakistan.
Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao, 266003, China; Department of Microbiology, Hazara University, Mansehra, Pakistan.
Harmful Algae. 2019 Jul;87:101630. doi: 10.1016/j.hal.2019.101630. Epub 2019 Jun 21.
Histones are the most abundant proteins associated with eukaryotic nuclear DNA. The exception is dinoflagellates, which have histone protein expression that is mostly reported to be below detectable levels. In this study, we investigated the presence of histone proteins and their functions in the dinoflagellate, Alexandrium pacificum. Histone protein sequences were analyzed, focusing on phylogenetic analysis and histone code. Histone expression was analyzed during the cell cycle and under nutritionally enhanced conditions using quantitative-PCR and western blots. Acid-soluble proteins were subjected to mass spectrometry analysis. To our knowledge, this is the first report of immunological detection of histone proteins (H2B and H4) in any dinoflagellate species. Absolute quantification of histone transcript in activily dividing cells revealed significant transcription in cells. The stable expression of histones during the cell cycle suggested that the histone genes in A. pacificum belonged to a replication-independent class and appeared to have a limited role in DNA packaging. The conservation of numerous post-translationally modified residues of multiple histone variants and differential expression of histones under nutritionally enhanced conditions suggested their functional significance in dinoflagellates. However, we detected histone H2B protein only via mass spectrometry. Histone-like protein was identified as most abundant acid-soluble protein of the cells.
组蛋白是与真核核 DNA 结合最丰富的蛋白质。例外是甲藻，其组蛋白蛋白表达大多被报道为低于可检测水平。在这项研究中，我们研究了组蛋白蛋白在甲藻亚历山大藻中的存在及其功能。分析了组蛋白蛋白序列，重点是系统发育分析和组蛋白密码。通过定量 PCR 和 Western blot 分析了细胞周期和营养增强条件下的组蛋白表达。将酸溶性蛋白进行质谱分析。据我们所知，这是首次在任何甲藻物种中检测到组蛋白蛋白（H2B 和 H4）的免疫检测。在活跃分裂的细胞中对组蛋白转录物进行绝对定量显示出细胞中有显著的转录。组蛋白在细胞周期中的稳定表达表明，A. pacificum 中的组蛋白基因属于复制非依赖性类，似乎在 DNA 包装中作用有限。许多组蛋白变体的翻译后修饰残基的保守性和营养增强条件下组蛋白的差异表达表明它们在甲藻中的功能意义。然而，我们仅通过质谱检测到组蛋白 H2B 蛋白。组蛋白样蛋白被鉴定为细胞中最丰富的酸溶性蛋白。
