oligodT18VN

OligodT18VN refers to a specific type of synthetic oligonucleotide primer used in molecular biology techniques, particularly in reverse transcription. The "oligo(dT)" portion indicates that the primer is composed of a string of deoxythymidine nucleotides. The "18" signifies that there are 18 thymidine nucleotides in the sequence. The "VN" at the end denotes a degenerate nucleotide mixture at the 3' end. Specifically, 'V' represents a mixture of A, C, or G nucleotides, while 'N' represents any of the four bases (A, T, C, or G). Therefore, an oligodT18VN primer has a sequence of 18 thymidines followed by a variable nucleotide at the 19th position, which can be A, C, or G, and a fully degenerate nucleotide at the 20th position. This design allows the primer to bind to the polyadenylated tail (poly(A) tail) of messenger RNA (mRNA) molecules at multiple starting points, even if the very end of the poly(A) tail is slightly degraded or modified. This degeneracy enhances the efficiency and reliability of first-strand cDNA synthesis from mRNA, which is crucial for applications like gene expression analysis, cDNA library construction, and RNA sequencing. The oligodT18VN primer is a modified form of the standard oligodT primer, offering greater flexibility in initiating reverse transcription.