Biology 1002B Chapter Notes - Chapter 9: Brca1, Zygote, Transfer Rna
13 Oct 2017
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Gene expression regulates changes that occur through determination and differentiation. Somites are blocks of mesoderm cells that form along both sides of the notochord. Under genetic control, some cells of each somite differentiate into skeletal muscle cells. First, paracrine signalling from nearby cells induces somite cells to express the master regulatory gene, myod. Product of myod is the transcription factor myod. By turning on specific muscle-determining genes, the action of myod brings about determination of these cells, converting them to undifferentiated muscle cells called myoblasts. Myod regulates genes such as myogenin and mef. Regulatory genes expressing transcription factors in myoblasts that turn on yet another set of genes. Products of these genes, including myosin, promote differentiation of myoblasts into specific types of muscle cells, such as skeletal muscle cells or cardiac muscle cells. Molecular mechanisms involved in determination and differentiation usually depend on regulatory genes that encode regulatory proteins that control the expression of other genes.
