Enzymatic rna synthesis

A method for template-independent synthesis of an RNA oligonucleotide, the method comprising:

• (a) providing an initiator oligonucleotide, wherein the initiator oligonucleotide is single-stranded RNA;
• (b) providing a poly(U) polymerase;
• (c) combining the initiator oligonucleotide, the poly(U) polymerase, and a 2′- and/or 3′-O-protected reversible terminator nucleotide under conditions sufficient for the addition of the 2′- and/or 3′-O-protected reversible terminator nucleotide to the 3′ end of the initiator oligonucleotide;
• (d) deprotecting the RNA oligonucleotide formed in step (c) at the protected 2′- and/or 3′-O-position of the 2′- and/or 3′-O-protected reversible terminator nucleotide;
• (e) optionally, repeating steps (a)-(c) until a desired RNA sequence is obtained.

A method for the synthesis of a RNA oligonucleotide, the method comprising:

• (a) providing a first oligonucleotide, wherein the first oligonucleotide comprises a 5′-triphosphate group;
• (b) providing a second oligonucleotide;
• (c) providing a poly(U) polymerase;
• (d) combining the first and second oligonucleotides and the poly(U) polymerase under conditions sufficient for the ligation of the first oligonucleotide to the 3′ end of the second oligonucleotide.

A compound of the following formula:

• or a salt thereof, wherein:
• Y is O or S;
• X is O or S;
• each instance of RP is hydrogen, an oxygen protecting group, optionally substituted acyl, or an amino acid, or two RP are joined together with the intervening atoms to form optionally substituted heterocyclyl;
• provided that at least one RP is an oxygen protecting group, optionally substituted acyl, or an amino acid;
• and
• “Base” is a natural or non-natural nucleotide base.

A compound of the following formula:

• or a salt thereof, wherein:
• Y is O or S;
• X is O or S;
• RP is an oxygen protecting group, optionally substituted acyl, or an amino acid;
• R is hydrogen, halogen, —CN, —NO2, —N3, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted acyl, optionally substituted hydroxyl, optionally substituted amino, or optionally substituted thiol;
• and
• “Base” is a natural or non-natural nucleotide base.

A compound of the following formula:

• or a salt thereof, wherein:
• Y is O or S;
• X is O or S;
• RP is an oxygen protecting group, optionally substituted acyl, or an amino acid;
• and
• “Base” is a natural or non-natural nucleotide base.