You seem confused. RNA polymerase is the enzyme that transcribes DNA into pre mRNA. So, the enzyme would transcribe the messenger RNA for its own protein construction.
DNA Polymerases DNA Polymerases
RNA polymerases
The RNA polymerases are huge multi-subunit protein complexes. Three kinds are found in eukaryotes: * RNA polymerase I (Pol I).It transcribes the rRNA genes for the precursor of the 28S, 18S, and 5.8S molecules (and is the busiest of the RNA polymerases). * RNA polymerase II (Pol II; also known as RNAP II).It transcribes protein-encoding genes into mRNA (and also the snRNA genes). * RNA polymerase III (Pol III).It transcribes the 5S rRNA genes and all the tRNAgenes.
An RNA virus whose genome is complementary to RNA and that carries mRNA polymerases necessary for the synthesis of a new virus.
RNA polymerase is the enzyme that makes mRNA from a strand of DNA.
DNA Polymerases DNA Polymerases
RNA is transcripted in the nucleus.
RNA molecules are synthesized by enzymes known as RNA POLYMERASES .http://www.answers.com/topic/rna-polymerasehttp://www.answers.com/topic/rna-polymerase
RNA polymerases
Polymerases are the enzymes that replicate and build nucleic acids. DNA polymerases synthesize DNA, RNA polymerases synthesize RNA. Purified polymerases are essential to carrying out the PCR reaction.
Various DNA polymerases read the DNA template during replication of DNA. Various RNA polymerases read the DNA template during transcription.
Enzymes
The RNA polymerases are huge multi-subunit protein complexes. Three kinds are found in eukaryotes: * RNA polymerase I (Pol I).It transcribes the rRNA genes for the precursor of the 28S, 18S, and 5.8S molecules (and is the busiest of the RNA polymerases). * RNA polymerase II (Pol II; also known as RNAP II).It transcribes protein-encoding genes into mRNA (and also the snRNA genes). * RNA polymerase III (Pol III).It transcribes the 5S rRNA genes and all the tRNAgenes.
PROMOTERS
rma polymerase 1, rna polymerase 2, rna polymerase 3
RNA and DNA polymerases are enzymes and hence, they are proteins.
Most DNA Polymerases and RNA polymerases have what is known as "proof-reading activity". This is the ability of the enzymes to check what bases they have added during DNA replication (in the case of DNA Polymerase) or transcription (in the case of RNA Polymerase), and if an error is found, splice it out and replace it with the correct base. The mode of action depends on the enzyme in question - some use endonucleases, and some use exonucleases; some work 5'-3' while others work 3'-5'. Also note that I said MOST polymerases have proof-reading capabilities...there are a few which do not (or don't proof-read very well).