Differential Gene Expression
Michael Barresi, Scott F. Gilbert
Abstract
This chapter reviews the evidence from molecular biology, cell biology, and somatic cell nuclear cloning that has shown that each cell of the body carries the same nuclear genome. It analyzes differential gene expression from genetically identical nuclei that creates different cell types and occurs at the levels of gene transcription, pre-mRNA processing, mRNA translation, and protein modification. It also shows how enhancer sequences regulate a gene's transcription in time and space. The chapter talks about DNA methylation, which can block transcription by preventing the binding of certain transcription factors or by recruiting histone methyltransferases or histone deacetylases to the chromatin. It covers Class A, B, C, D, and E transcription factors that function as homeotic regulators of floral organ identity.