Prithika Udayakumar, Vikneswari Ramaraj, Balamurugan Krishnaswamy
Department of Biotechnology, Science Campus, Alagappa University, Karaikudi, 630 003 Tamil Nadu, India.
Department of Biotechnology, Science Campus, Alagappa University, Karaikudi, 630 003 Tamil Nadu, India.
Immunobiology. 2017 Apr;222(4):684-692. doi: 10.1016/j.imbio.2016.12.008. Epub 2016 Dec 30.
One of the key issues pertaining to the control of memory is to respond to a consistently changing environment or microbial niche present in it. Human cyclic AMP response element binding protein (CREB) transcription factor which plays a crucial role in memory has a homolog in C. elegans, crh-1. crh-1 appears to influence memory processes to certain extent by habituation of the host to a particular environment. The discrimination between the pathogen and a non-pathogen is essential for C. elegans in a microbial niche which determines its survival. Training the nematodes in the presence of a virulent pathogen (S. aureus) and an opportunistic pathogen (P. mirabilis) separately exhibits a different behavioural paradigm. This appears to be dependent on the CREB transcription factor. Here we show that C. elegans homolog crh-1 helps in memory response for a short term against the interacting pathogens. Following conditioning of the nematodes to S. aureus and P. mirabilis, the wild type nematodes exhibited a positive response towards the respective pathogens which diminished slowly after 2h. By contrast, the crh-1 deficient nematodes had a defective memory post conditioning. The molecular data reinforces the importance of crh-1 gene in retaining the memory of nematode. Our results also suggest that involvement of neurotransmitters play a crucial role in modulating the memory of the nematode with the assistance of CREB. Therefore, we elucidate that CREB is responsible for the short term memory response in C. elegans against bacterial pathogens.
与记忆控制相关的关键问题之一是对不断变化的环境或其中存在的微生物生态位做出反应。人类环磷酸腺苷反应元件结合蛋白（CREB）转录因子在记忆中起关键作用，在秀丽隐杆线虫中有一个同源物crh-1。crh-1似乎通过使宿主适应特定环境在一定程度上影响记忆过程。对于秀丽隐杆线虫在决定其生存的微生物生态位中而言，区分病原体和非病原体至关重要。分别在有毒力的病原体（金黄色葡萄球菌）和机会致病菌（奇异变形杆菌）存在的情况下对线虫进行训练，会表现出不同的行为模式。这似乎依赖于CREB转录因子。在这里我们表明，秀丽隐杆线虫的同源物crh-1有助于在短期内对相互作用的病原体产生记忆反应。在将线虫分别适应金黄色葡萄球菌和奇异变形杆菌后，野生型线虫对相应病原体表现出阳性反应，2小时后这种反应缓慢减弱。相比之下，crh-1缺陷型线虫在适应训练后存在记忆缺陷。分子数据强化了crh-1基因在保留线虫记忆方面的重要性。我们的结果还表明，神经递质的参与在CREB的协助下对线虫记忆的调节起着关键作用。因此，我们阐明CREB负责秀丽隐杆线虫对细菌病原体的短期记忆反应。
