HNRNPD
Description
The HNRNPD (heterogeneous nuclear ribonucleoprotein D) is a protein-coding gene located on chromosome 4.
HNRNPD, also known as AU-rich element RNA-binding protein 1 (AUF1), is a protein encoded by the HNRNPD gene in humans. Alternative splicing of this gene results in four transcript variants. HNRNPD belongs to the subfamily of ubiquitously expressed heterogeneous nuclear ribonucleoproteins (hnRNPs). hnRNPs are nucleic acid binding proteins that complex with heterogeneous nuclear RNA (hnRNA). The interaction sites on the RNA are frequently biased towards particular sequence motifs. These proteins are associated with pre-mRNAs in the nucleus and appear to influence pre-mRNA processing and other aspects of mRNA metabolism and transport. While all hnRNPs are present in the nucleus, some shuttle between the nucleus and cytoplasm. hnRNP proteins have distinct nucleic acid binding properties. HNRNPD contains two repeats of quasi-RRM domains that bind to RNAs. It localizes to both the nucleus and the cytoplasm.
HNRNPD binds with high affinity to RNA molecules containing AU-rich elements (AREs) located within the 3'-UTR of many proto-oncogenes and cytokine mRNAs. It also binds to double- and single-stranded DNA sequences in a specific manner, acting as a transcription factor. Each of its RNA-binding domains binds preferentially to a single-stranded non-monotonous 5'-UUAG-3' sequence and, to a lesser extent, to the single-stranded 5'-TTAGGG-3' telomeric DNA repeat. HNRNPD binds RNA oligonucleotides with 5'-UUAGGG-3' repeats more tightly than the telomeric single-stranded DNA 5'-TTAGGG-3' repeats. The binding of its RRM1 domain to DNA inhibits the formation of DNA quadruplex structures, potentially playing a role in telomere elongation. HNRNPD might be involved in translationally coupled mRNA turnover. It is implicated with other RNA-binding proteins in the cytoplasmic deadenylation/translational and decay interplay of the FOS mRNA mediated by the major coding-region determinant of instability (mCRD) domain. HNRNPD may play a role in regulating the rhythmic expression of circadian clock core genes. It directly binds to the 3'-UTR of CRY1 mRNA and induces rhythmic CRY1 translation. HNRNPD may also be involved in regulating PER2 translation.
HNRNPD is also known as AUF1, AUF1A, HNRPD, P37, hnRNPD0.
