Transcription produces messenger RNA (mRNA) molecules. During the transcription process, the DNA sequence of a gene is copied into a complementary RNA sequence. This is the first step in the process of gene expression, which ultimately leads to the production of proteins.
In more detail, the enzyme RNA polymerase binds to the DNA at a specific region called the promoter. It then unwinds the DNA strands and synthesizes the RNA strand by adding complementary RNA nucleotides based on the DNA template. The result is a single-stranded mRNA molecule that carries the genetic information from the DNA out of the nucleus and into the cytoplasm, where it will be translated into a protein.