St. Thomas, St. John, and St. Croix-the three islands known to many as the U.S. Virgin Islands, and the reason millions of travelers head to the Caribbean every year.
This copying process is called transcription and the copy is mRNA. Transcription takes place in the cytoplasm (prokaryote) or in the nucleus (eukaryote). The transcription is performed by an enzyme called RNA polymerase. To make mRNA, RNA polymerase: 1  Binds to the DNA strand at a specific sequence of the gene called a promoter. 2  Unwinds and unlinks the two strands of DNA. 3  Uses one of the DNA strands as a guide or template.
RNA Processing. The RNA copy of a protein encoding gene must be modified in several ways before it can be transported out of the nucleus and translated into protein. The primary transcription product of a gene is therefore called a precursor of mRNA, pre-mRNA. Both ends of the pre-mRNA are modified. An additional nucleotide, a 7-methylguanosine is added to the 5'-end to form a cap-structure. This process is called capping (1) . The 3'-end of the pre-mRNA is cleaved and polyadenylated (4) .