What is the earliest expressed component of ECM during embryonic development?

During embryonic development, laminin is significant as an early extracellular matrix (ECM) component. Laminin is a large glycoprotein that serves a critical role in cell adhesion, differentiation, and migration, essential processes in early embryogenesis. Its presence helps to form the basal lamina, which supports the structure of tissues and organs being formed. Laminin's expression is among the first to occur in the development stages, facilitating the organization of cells into tissues by providing a scaffold for cellular attachment and promoting various cellular interactions.

In contrast, while actin is crucial for cell structure and motility, it is not a component of the ECM but rather a cytoskeletal protein. Tenascin and fibronectin are also important ECM proteins that play roles later in development and tissue repair but are typically expressed after laminin during the early stages of embryonic development.