Alternative titles; symbols
HGNC Approved Gene Symbol: HNRNPAB
Cytogenetic location: 5q35.3 Genomic coordinates (GRCh38): 5:178,204,533-178,211,163 (from NCBI)
Apolipoprotein B (APOB; 107730) mRNA editing is an intranuclear function and is mediated by a multiprotein editosome complex (see APOBEC1; 600130). Using the yeast 2-hybrid system, Lau et al. (1997) identified an APOBEC1-binding protein (ABBP1) that interacts with APOB mRNA. The ABBP1 cDNA encodes a 331-amino acid protein that is identical to the human type A/B heterogeneous nuclear ribonucleoprotein (hnRNP) reported by Khan et al. (1991), except for a 47-residue insertion in its C-terminal region. Khan et al. (1991) identified the type A/B hnRNP as an RNA-binding protein of unknown function in HeLa cells. Northern blot analysis indicated that ABBP1 mRNA is distributed in multiple human tissues as an approximately 2-kb transcript. The 47-amino acid insertion of ABBP1 is encoded by an alternatively spliced exon.
Lau et al. (1997) found that ABBP1 contains typical RNP-type RNA-binding motifs in its N-terminal half and glycine-rich motifs, which house the APOBEC1-binding region, in its C-terminal region. ABBP1 binds to APOB mRNA transcripts around the editing site and can be UV-crosslinked to them. Editing is inhibited by ABBP1 immunodepletion or antisense ABBP1 cDNA transfection.
Khan, F. A., Jaiswal, A. K., Szer, W. Cloning and sequence analysis of a human type A/B hnRNP protein. FEBS Lett. 290: 159-161, 1991. [PubMed: 1717314] [Full Text: https://doi.org/10.1016/0014-5793(91)81249-8]
Lau, P. P., Zhu, H.-J., Nakamuta, M., Chan, L. Cloning of an apobec-1-binding protein that also interacts with apolipoprotein B mRNA and evidence for its involvement in RNA editing. J. Biol. Chem. 272: 1452-1455, 1997. [PubMed: 8999813] [Full Text: https://doi.org/10.1074/jbc.272.3.1452]