E2f3 Conditional Knockout mouse models

E2f3, the mouse ortholog of human E2F3, encodes the most proliferation-critical activator E2F and produces two isoforms from alternative promoters, E2F3a induced at the G1/S boundary and E2F3b expressed constitutively, both heterodimerizing with DP proteins and both repressed by RB pocket binding until CDK mediated phosphorylation. E2F3 loss reduces expression of the core replication program more severely than loss of E2F1 or E2F2, and E2F3 amplification at 6p22 drives bladder and small cell lung carcinoma, while E2F3 is also required for the proliferative burst that follows RB inactivation, making it the principal mediator of RB pathway dependency. Null viability is strongly strain dependent, with most nulls dying perinatally on inbred backgrounds, so conditional floxed alleles and isoform-specific knockins are the safer design. Given real redundancy with E2f1 and E2f2, compound conditional stocks are needed to expose requirement. Choose isoform-specific alleles when the question is RB pathway output versus constitutive housekeeping transcription.

Conditional deletion of E2f3 limits the genetic change to the lineage you choose. That helps in oncology, immunology, and metabolic work where systemic loss would muddy the read. After you confirm Cre specificity, crossing to E2f3 floxed stock yields usable cohorts.