Structural genes

Structural genes are a type of gene that codes for any RNA or protein product other than a regulatory factor. They are responsible for the synthesis of proteins that function in the structure of the organism or cell, or that act as enzymes in metabolic pathways.

Overview

Structural genes are distinct from regulatory genes, which produce products that control or regulate the expression of other genes. In prokaryotes, structural genes are often grouped together in an operon and are transcribed together under the control of a single promoter. In eukaryotes, each structural gene typically has its own promoter, and is transcribed separately.

Function

The primary function of structural genes is to produce proteins that become part of the cell's structure or that carry out metabolic functions. For example, structural genes may code for the proteins that make up the cell's cytoskeleton, or for enzymes that catalyze the reactions of metabolism.

Regulation

The expression of structural genes is tightly regulated to ensure that the correct proteins are produced in the right amounts at the right time. This regulation is typically achieved through the action of transcription factors, which bind to the promoter region of the gene and either stimulate or inhibit transcription.

Examples

Examples of structural genes include the lacZ, lacY, and lacA genes in the lac operon of Escherichia coli. These genes code for the enzymes beta-galactosidase, permease, and transacetylase, respectively, which are involved in the metabolism of lactose.

See also

• Operon
• Regulatory gene
• Promoter (genetics)
• Transcription (genetics)