The transcription factor IID subunit Taf13 is dispensable for TATA binding protein promoter recruitment and RNA polymerase II transcription

The multiprotein complex TFIID, comprising the TATA binding protein (TBP) and 13 TBP-associated factors (TAFs), is an essential component of the RNA polymerase II (Pol II) preinitiation complex (PIC). Cryo-electron microscopy studies suggested a critical role of the TAF11-TAF13 heterodimer in TBP promoter deposition upstream of the transcription start site. To investigate this hypothesis, we inactivated the gene encoding Taf13 in mice and embryonic stem cells (ESCs). Taf13-null embryos implant and survive until E6.5, but fail to undergo gastrulation, while Taf13-null ESCs are viable, but fail to form embryoid bodies and differentiate. Taf13 loss had little effect on TFIID integrity and led to only a mild reduction of TBP promoter recruitment, but led to altered PIC formation and globally reduced Pol II recruitment. Thus, the Taf11-Taf13 heterodimer is not essential for TBP/TFIID recruitment, revealing plasticity in the pathways of PIC formation.