Gene expression studies in giardia lambia

多细胞生物（如人类）的每个细胞都包含相同的基因蓝图——那么是什么使血细胞与肌肉细胞不同呢？答案是遗传物质是如何被激活的。不同的细胞类型会激活不同的基因来制造特定细胞功能的蛋白质。例如，血细胞会产生一种蛋白质，用于将氧气输送到全身，而肌肉细胞会产生一种蛋白质，用于细胞收缩。这种差异基因激活的过程被称为基因表达。基因表达的控制发生在细胞内的许多层面，但最常见的控制是在转录的起始阶段。转录是制造特定基因“复印件”的机制。这些拷贝被称为信使RNA (mRNA)，它们作为蛋白质生产的指令。转录的起始是通过特定因子的有序组装来严格控制的，这些因子识别并结合在启动子区域的特定DNA序列上，启动子位于每个基因的开始之前。我的兴趣是研究基因表达，特别是在单细胞原生动物，贾第鞭毛虫转录起始的调控。这种微生物是全世界人类感染性腹泻的最常见原因，也是加拿大淡水中常见的污染物。贾第鞭毛虫是一种真核生物，就像人类细胞一样，因为它的基因位于细胞内一个叫做细胞核的特殊区域。然而，与人类细胞相比，贾第鞭毛虫中控制转录起始的调控区域更小，更不复杂，并且与人类细胞相比，贾第鞭毛虫中转录起始前在这些区域聚集所需的因子数量似乎大大减少。因此，研究贾第鞭毛虫的转录和基因表达将是一个机会，可以在一个流线型生物系统中确定这些过程的基本要素。此外，这些研究可能确定贾第鞭毛虫这些途径的独特方面，可用于开发改进和更有效的贾第鞭毛虫感染治疗方法。

Every cell within a multicellular organism, such as a human, contains the same genetic blueprint - so what makes a blood cell different from a muscle cell? The answer is how the genetic material is activated. Different cell types activate different sets of genes to make proteins that are specific for the function of the particular cell. For example, a blood cell would produce a protein for carrying oxygen through the body, while a muscle cell would produce a protein that is used for cell contraction. The process of this differential gene activation is referred to as gene expression. The control of gene expression occurs at many levels within a cell but the most common level of control is at the initiation of transcription. Transcription is the mechanism that makes 'photocopies' of particular genes. These copies are called messenger RNA (mRNA), and they serve as the instructions for the production of proteins. The initiation of transcription is tightly controlled through the orderly assembly of specific factors that recognize and bind to specific DNA sequences in regions called promoters, which precede the beginning of each gene. I am interested in studying gene expression, in particular the regulation of transcription initiation in the single cell protozoan, Giardia lamblia. This organism is the most common cause of infectious diarrhea in humans worldwide, and is a frequent contaminant of freshwaters in Canada. Giardia is an eukaryote, like a human cell, because its genes are located in a special compartment within the cell called the nucleus. However, the regulatory regions for the control of transcription initiation in Giardia are smaller and less complex than those in a human cell, and the number of factors that are required to assemble at these regions before transcription can initiate appears to be greatly reduced in Giardia compared to a human cell. Therefore, the study of transcription and gene expression in Giardia would be an opportunity to identify the bare essentials of these processes in a streamlined biological system. Moreover, these studies may identify unique aspects of these pathways in Giardia that can be exploited to develop improved and more effective treatments of Giardia infections.