misincorporated

Misincorporated is the past participle of misincorporate and is used to describe an element that has been inserted into a growing polymer or macromolecule in an incorrect or unintended way. In biology, misincorporation most often refers to the incorrect insertion of a nucleotide during nucleic acid synthesis or errors in translating genetic information into protein.

In DNA replication, misincorporation occurs when a DNA polymerase adds the wrong nucleotide opposite the template strand. High fidelity is maintained by proofreading exonuclease activity and by post-rereplication mismatch repair, but some misincorporations escape these safeguards. If not corrected, a misincorporated base can result in a heritable mutation after subsequent rounds of replication. The types and frequencies of errors depend on enzyme fidelity, the balance of nucleotide pools, and external mutagens.

In transcription, misincorporation happens when RNA polymerases insert incorrect ribonucleotides. Transcription has lower fidelity than DNA replication, so misincorporated transcripts are produced more frequently. These errors can affect RNA function and may be transient, since damaged or faulty transcripts are often degraded or avoided by cellular quality control mechanisms.

In translation, misincorporation refers to inserting the wrong amino acid into a growing polypeptide, typically due to tRNA misselection or mischarging. Misincorporations can alter protein structure and activity, and cells rely on chaperones and proteolytic pathways to mitigate detrimental effects.

Overall, misincorporation is a source of genetic and proteomic variation and a target for cellular quality control systems. It is also a focus of research into mutagenesis, enzyme fidelity, and the consequences of errors in gene expression.