Picaridin can be used on human skin or clothing to repel mosquitoes, biting flies, ticks, fleas, and chiggers. These products may be pump sprays, liquids, aerosols, or wipes.
Transcription is carried out by a DNA-dependent RNA polymerase that copies the sequence of a DNA strand into RNA. To begin transcribing a gene, the RNA polymerase binds to a sequence of DNA called a promoter and separates the DNA strands.
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) .