Protein: Interleukin enhancer-binding factor 3-A (CCAAT box transcription factor subunit) (Double-stranded RNA-binding protein 4F.1) (DsRNA-binding protein 4F.1) (Q91550)
Organism: Xenopus laevis (African clawed frog)
Function: RNA-binding protein that plays an essential role in the biogenesis of circular RNAs (circRNAs) which are produced by back-splicing circularization of pre-mRNAs. Within the nucleus, promotes circRNAs processing by stabilizing the regulatory elements residing in the flanking introns of the circularized exons (By similarity). Plays thereby a role in the back-splicing of a subset of circRNAs (By similarity). As a consequence, participates in a wide range of transcriptional and post-transcriptional processes (By similarity). Binds to poly-U elements and AU-rich elements (AREs) in the 3'-UTR of target mRNAs (By similarity). Upon viral infection, ILF3 accumulates in the cytoplasm and participates in the innate antiviral response (By similarity). Mechanistically, ILF3 becomes phosphorylated and activated by the double-stranded RNA-activated protein kinase/PKR which releases ILF3 from cellular mature circRNAs. In turn, unbound ILF3 molecules are able to interact with and thus inhibit viral mRNAs (By similarity). Has a cytoplasmic role early in development as part of a ribonucleoprotein (mRNP) complex which may regulate mRNA transport and/or translation. Following nuclear localization at the mid-blastula transition, acts as a transcription factor and binds the 5'-CCAAT-3' promoter sequence to regulate transcription of the gata2 gene as a subunit of the CCAAT box transcription factor (CBTF). Its role as an mRNP component negatively regulates its activity as a transcription factor by precluding its nuclear localization.
Subcellular location: Nucleus {ECO:0000269|PubMed:10899122, ECO:0000269|PubMed:9710639}. Cytoplasm {ECO:0000269|PubMed:10899122, ECO:0000269|PubMed:9710639}. Note=Cytoplasmic in fertilized eggs, then translocates to the nucleus prior to gastrulation. RNA-binding is required for cytoplasmic retention during early development, and nuclear translocation at the mid-blastula transition (MBT) is probably coupled to the degradation of maternal mRNA that occurs at that stage. {ECO:0000269|PubMed:10899122, ECO:0000269|PubMed:9710639}.
Interaction partners:
Sequence:
MRPMRIFLNDDRHVMAKHSVVYPTQEELEAVQNMVSHTERALKAVSDWIDQQEKDCSGEQEQPMAEETETTEEGKDSEMKTGENPTRTLRGVMRVGLVAKGLLLKGDLDLELVLLCRDKPTISLLKRVADNLVLQFETVSEDKYEVIQNIREALIVVKSTKEPPLTLNIRLTSPLVREEMEKLSAGETLTVSDPPDVLDRHKCLAALASLRHAKWFQARANGLKSCVIVIRVLRDLCTRVPTWEPLRGWPLELLCEKAIGTANRPMGAGEALRRVLECLSSGILMPDGSGLYDPCEKDASDALEHLERQQREDITQSAQHALRLAAFGQLHKVLGMDPLPSKMPKKTKVETPVIDYTVQIPPSTTYAMPPLKRPIEEDGDDKSPSKKKKKIQKKDEKSEPPQVMNALMRLNQLKPGLQYKLISQTGPVHAPVFTMSVEVDDKTFEASGPSKKTAKLHVAVKVLQDMGLPTGMEEKEEGTDESEQKPVVQTPAQPDDSAEVDSAALDQAESAKQQGPILTKHGKNPVMELNEKRRGLKYELISETGGSHDKRFVMEVEVDGVKFQGSGSNKKVAKAYAALSALEKLFPDYTMYTEAPKKKRPPMMPRGGPKFAGKHNQGFGMMYSEVPPPQAMRGRGRGGMNRGRGRGRGGFGGGYMNSGGYGGGYGGNYNYQTSATAGYSQFYSNGGASGNAGGGGAGTGGYSSYYQGDSYSAPTPPKPFVNKKPPPPQQQQQQQPPPQHASNPPKPSYNQGYQGHQGGQQQQQQQQQQQTYNQNQYSNYGPPQKQKGGYNQGAQGAGSGGSYNYSNSYTGGTAPLGTAVERVQEGEAAALTQRQALVTTQAHTPAMVEPAVLRRTKVTRSLITIKVPPDRTTVALQIITSSLREELGVTAGIQNTT