BIO411: Genome Regulation - Cytoplasmic Determinants

Cytoplasmic Determinants and Inductive Signals

• Egg cytoplasm contains RNA, proteins, and other substances distributed unevenly, influencing early development.
• Cytoplasmic determinants are maternal substances in the egg that influence early development.
• As the zygote divides by mitosis, cells contain different cytoplasmic determinants, leading to different gene expression.
• The environment around the cell, especially signals from nearby embryonic cells, provides developmental information.
• Induction: signal molecules from embryonic cells cause transcriptional changes in nearby target cells, inducing differentiation of specialized cell types.

Sequential Regulation of Gene Expression

• Determination commits a cell to its final fate.
• Determination precedes differentiation.
• Cell differentiation is marked by the production of tissue-specific proteins.

Pattern Formation: Setting Up the Body Plan

• Pattern formation is the development of a spatial organization of tissues and organs.
• In animals, pattern formation begins with the establishment of the major axes.
• Positional information provides molecular cues that control pattern formation, telling a cell its location relative to the body axes and neighboring cells.

The Life Cycle of Drosophila

• Cytoplasmic determinants in the unfertilized Drosophila egg determine the axes before fertilization.
• After fertilization, the embryo develops into a segmented larva with three larval stages.

Learn about the role of cytoplasmic determinants and inductive signals in genome regulation, including the distribution of RNA, proteins, and other substances in the unfertilized egg.