Molecular Biology

Molecular Biology

Molecular biology is a branch of biology that seeks to understand how cells function by studying the molecules that make them up, such as nucleic acids (DNA and RNA) and proteins.

DNA and ARN

DNA is one of the main focuses in molecular biology. It contains all the information needed for a cell to function. The information contained in DNA is copied into RNA in a process called transcription. The RNA is then translated into proteins.

Transcription factors

The human genome contains approximately 20,000 genes that code for various proteins. To control which genes are activated in a cell at specific times, transcription factors exist. These proteins bind to specific parts of the DNA to either activate or block the reading of genes, depending on the needs of the cell. Several teams within the RQR focus on different transcription factors. For example, Jacques Drouin’s lab studies the transcription factors Pitx1 and Tpit, which play important roles in the development of the pituitary gland, an endocrine gland located at the base of the brain. Nicolas Gévry’s team studies the role of the transcription factors NR5A1 and NR5A2 in the ovary and fertility. Raj Duggavathi works on transcription factors involved in the ERK1/2 intracellular signaling pathways, as well as key molecules involved in ovulation, including Nr5a2, mTOR, and Fabp6.

Transcription factors from the GATA family are known to play an important role in the function of the heart and the digestive system. Robert S. Viger’s team studies GATA transcription factors in the context of early development of the testis and ovary, sexual differentiation, and steroidogenesis.

Signaling pathways

Transcription factors themselves are regulated by signaling pathways—that is, chains of chemical reactions triggered by signals (for example, hormones) coming from outside the cell. These signals bind to receptors located on the surface of cells, which then transmit the information inside to modify cellular behavior. Information inside cells can be transmitted by small signaling molecules such as cAMP and cGMP. These molecules, also known as cyclic nucleotides, are the subject of François Richard’s research, particularly regarding their role in oocytes. Derek Boerboom’s team studies signaling pathways such as Wnt, Hippo, and Slit/Robo, which are known for their role in embryonic development. However, it has become clear that these “developmental” pathways are also involved in adult life, and their roles in this context are just beginning to be explored. In particular, the overactivation of these signaling pathways can be linked to the development of reproductive system cancers such as ovarian, uterine, and breast cancers. Daniel Dufort’s lab studies the role of Nodal and Wnt signaling pathways in embryo implantation, placenta formation, and the initiation of labor.

Molecular mechanisms

RNA produced from gene transcription is usually immediately translated into proteins. However, in oocytes, RNA accumulates to be translated into proteins later. This phenomenon is being studied by Hugh J. Clarke’s team. This team is also investigating the molecular mechanisms that allow oocytes to communicate with the surrounding cells—a communication that is essential for normal oocyte development.

Infections and other environmental stressors can affect the process of translating RNA into proteins. Notably, Maritza Jaramillo studies why and how some infected placental cells poorly produce proteins from their RNA. This could disrupt the expression of genes required for embryo implantation, proper placenta development, and its normal functioning.

Cristian O’Flaherty’s team is working to understand how sperm cells mature and how this process can be influenced by molecules called reactive oxygen species (ROS), which are naturally produced by the body but can sometimes damage cells.

Molecular biology approaches

Molecular biology approaches are very useful for answering scientific questions related to reproduction. RQR researchers use these approaches daily in their work. For example, Daniel Cyr develops specialized tools to better understand how epididymal cells (in the male reproductive system) transform and specialize, by studying the signals and mechanisms that control this process. Julie Brind’Amour uses molecular biology tools to answer questions about the early days of embryonic development. Kalidou Ndiaye’s team seeks to understand the expression and function of genes that may influence ovarian function, oocyte quality, and fertility in cattle.

Molecular biology also focuses on molecules involved in cell movement. Aimee Ryan’s lab studies proteins called claudins, which play a key role in the junctions between cells and may be involved in embryonic development.

Finally, Xianming Zhang’s team seeks to understand the role of molecules considered as organic contaminants on health. This team develops environmental and molecular models to simulate environmental processes, exposure, and the impact of these contaminants.