A 3.5-kb segment of DNA containing the complete sequence of a mouse gene is available. The DNA segment contains the promoter sequence and extends beyond the polyadenylation site of the gene. The DNA is studied by band shift assay (see Research Technique 8.1), and the following gel bands are observed. Match these conditions to a specific lane of the gel. 3.5-kb fragment plus RNA polymerase II

Key Concepts

Promoter Sequence

The promoter sequence is a region of DNA located upstream of a gene that initiates transcription. It serves as the binding site for RNA polymerase and transcription factors, facilitating the assembly of the transcription machinery. Understanding the promoter's role is crucial for analyzing gene expression and the effects of regulatory elements.

RNA Polymerase II

RNA polymerase II is an enzyme responsible for synthesizing mRNA from a DNA template during transcription. It recognizes and binds to the promoter region of genes, unwinding the DNA to initiate RNA synthesis. Its interaction with the promoter and other regulatory proteins is essential for proper gene expression and regulation.

Gel Electrophoresis

Gel electrophoresis is a laboratory technique used to separate DNA, RNA, or proteins based on their size and charge. In this method, samples are loaded into a gel matrix and subjected to an electric field, causing molecules to migrate at different rates. Analyzing the resulting bands allows researchers to determine the presence and size of specific nucleic acid fragments, aiding in the interpretation of experimental results.