To date, serine integrases have not been used extensively in plant systems

sequential lineage tracing studies aimed at unraveling the relationships between cellular precursors and mature cell types

in the absence of tamoxifen, it exhibits some activity

A technique common in rodents is the use of Cre recombinase lines that are inducible at specific developmental time points (Figure 3b). The most common form of inducible Cre is CreERT2, which contains a modified estrogen receptor binding domain that prevents Cre from entering the nucleus in the absence of a ligand

strong promoters capable of driving expression of microbial opsins or fluorescent proteins in specific populations can exhibit leaky expression elsewhere. This low-level leak may be virtually undetectable as light responsiveness or fluorescence but can be a serious issue when expressing Cre recombinase.

Over 20 orthogonal serine integrases have been characterized to date (6,11), and many now have identified RDFs.

DNA fragment assembly using site-specific recombination by ϕC31 integrase

uses of serine integrases for synthetic biology applications; for assembly of long arrays of genes or other DNA fragments, creation of genetic switches, circuits and logic systems, and for permanent genomic recording of cellular events

unique selling point of the latter systems is their one-way directional nature

attP and attB sites for serine integrases are both short (attP ∼50 bp; attB ∼40 bp); each site is bound by a dimer of integrase, and no host-encoded proteins are required

attB and attP sites are typically ≤ 50 bp with different inverted repeat sequences flanking 2 to 12 bp of complementary sequence, which includes the recombination crossover point

using recombinases can be challenging because their reactions are slow (requiring 2–6 h) and often generate mixed populations when targeting a multicopy plasmid