Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Plos One e17216 2011 fdi:010053365 ENG Plos One 1932-6203 ISI:000287761700036 2 10.1371/journal.pone.0017216 https://www.documentation.ird.fr/hor/fdi:010053365 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers17-08/010053365.pdf 6 Horizon (IRD) General transcription factor IIB (TFIIB) and TFIIB-related factor (BRF), are conserved RNA polymerase II/III (RNAPII/III) selectivity factors that are involved in polymerase recruitment and transcription initiation in eukaryotes. Recent findings have shown that plants have evolved a third type of B-factor, plant-specific TFIIB-related protein 1 (pBRP1), which seems to be involved in RNAPI transcription. Here, we extend the repertoire of B-factors in plants by reporting the characterization of a novel TFIIB-related protein, plant-specific TFIIB-related protein 2 (pBRP2), which is found to date only in the Brassicacea family. Unlike other B-factors that are ubiquitously expressed, PBRP2 expression is restricted to reproductive organs and seeds as shown by RT-PCR, immunofluorescence labelling and GUS staining experiments. Interestingly, pbrp2 loss-of-function specifically affects the development of the syncytial endosperm, with both parental contributions required for wild-type development. pBRP2, is the first B-factor to exhibit cell-specific expression and regulation in eukaryotes, and might play a role in enforcing bi-parental reproduction in angiosperms. 076 UR121