Kummasook Aksarakorn, Pongpom Patthama, Vanittanakom Nongnuch
Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
DNA Seq. 2007 Oct;18(5):385-94. doi: 10.1080/10425170701309012.
A gene encoding heat shock protein 70 (Hsp70) of Penicillium marneffei was isolated and characterized. The structure of P. marneffei hsp70 gene was similar to hsp70 genes of other organisms, with a unique sequence of 3-nt microexon flanked by two introns. Comparison of the deduced amino acid sequence revealed that the Hsp70 was grouped in the fungal cytosolic Hsp70s. Northern blot analysis demonstrated the upregulation of hsp70 expression during the mycelium to yeast phase transition. Upregulation was also observed during yeast or mycelial cells encountering heat shock condition at 39 degrees C. Experimental analysis showed that the expression of hsp70 is temperature dependent. Contradictory, a severe heat shock condition at 42 degrees C resulted in lowering the hsp70 transcript. Reverse transcription-polymerase chain reaction (RT-PCR) showed the accumulation of a large population of mature mRNA and small population of intron II-unspliced hsp70 mRNA in most cell types (conidia, mycelia and yeast). These results suggested that the Hsp70 may play an important role in environmental stress response and adaptation.
分离并鉴定了一株马尔尼菲青霉菌热休克蛋白70（Hsp70）的编码基因。马尔尼菲青霉菌hsp70基因的结构与其他生物的hsp70基因相似，具有一段独特的3个核苷酸的微小外显子序列，两侧各有一个内含子。对推导的氨基酸序列进行比较后发现，该Hsp70归属于真菌胞质Hsp70家族。Northern印迹分析表明，在菌丝体向酵母相转变过程中hsp70表达上调。在酵母或菌丝体细胞遭遇39℃热休克条件时也观察到上调现象。实验分析表明，hsp70的表达具有温度依赖性。矛盾的是，42℃的严重热休克条件导致hsp70转录本减少。逆转录-聚合酶链反应（RT-PCR）显示，在大多数细胞类型（分生孢子、菌丝体和酵母）中，大量成熟mRNA和少量内含子II未剪接的hsp70 mRNA积累。这些结果表明，Hsp70可能在环境应激反应和适应中发挥重要作用。
