Structure and expression of the gene (HNRPA2B1) encoding the human hnRNP protein A2/B1

doi:10.1016/0888-7543(95)80035-K

Genomics

Volume 25, Issue 2, 20 January 1995, Pages 365-371

https://doi.org/10.1016/0888-7543(95)80035-K Get rights and content

Abstract

Heterogeneous nuclear ribonucleoprotein (hnRNP) A2 is a major nuclear protein and one of the major components of the hnRNP core complex in mammalian cells. We first determined the complete sequence of the human gene for hnRNP protein A2 (HNRPA2B1). The human HNRPA2B1 gene exists in a single copy over 9 kb in length. The gene was split into 12 exons, including a 36-nucleotide mini-exon, which was specific to the hnRNP protein B1, providing genetic evidence that the B1 mRNA was generated from the primary HNRPA2B1 transcript by alternative splicing. The 5′ region of HNRPA2B1 was GC-rich and contained several DNA motifs for the binding of several transcription factors, which included 2 CCAAT boxes and no TATA sequences. The 5′ ends of the mRNA were mapped to multiple positions. These structural features are characteristic of promoter regions of housekeeping genes. Northern blot and RT-PCR analyses of the HNRPA2B1 transcripts revealed levels of B1 mRNA from 2 to 5% of total A2/B1 transcripts and showed that both A2 and B1 mRNAs were transcribed in all human cell lines and mouse tissues studied. The structural and evolutionary characteristics of the A2 and A1 proteins as they relate to each other are discussed.

References (38)

S.F. Altschul et al.
Basic local alignment search tool
J. Mol. Biol.
(1990)
A.L. Beyer et al.
Identification and characterization of the packaging proteins of core 40S hnRNP particles
Cell
(1977)
G. Biamonti et al.
Isolation of an active gene encoding human hnRNP protein A1
J. Mol. Biol.
(1989)
G. Biamonti et al.
Human hnRNP protein A1 gene expression. Structural and functional characterization of the promoter
J. Mol. Biol.
(1993)
P. Chomczynski et al.
Single-step method of RNA acid guanidinium thiocyanate—phenol—chloroform extraction
Anal. Biochem.
(1987)
T. Kallunki et al.
Structure of the human laminin B2 chain gene reveals extensive divergence from the laminin B1 chain gene
J. Biol. Chem.
(1991)
J.D. Keene et al.
Nuclear RNA-binding proteins
Prog. Nucleic Acid Res. Mol. Biol.
(1991)
J.T. Knowler
An assessment of the evidence for the role of ribonucleoprotein particles in the maturation of eukaryote mRNA
Int. Rev. Cytol.
(1983)
A. Mayeda et al.
Regulation of alternative pre-mRNA splicing by hnRNP A1 and splicing factor SF2
Cell
(1992)
S.F. Barnett et al.
The core proteins A2 and B1 exist as (A2)3B1 tetramers in 40S nuclear ribonucleoprotein particles
Mol. Cell. Biol.
(1991)

C.G. Burd et al.

Primary structures of the heterogeneous nuclear ribonucleoprotein A2, B1, and C2 proteins: A diversity of RNA binding proteins is generated by small peptide inserts

Proc. Natl. Acad. Sci. USA

(1989)

M. Buvoli et al.

cDNA cloning of human hnRNP protein A1 reveals the existence of multiple mRNA isoforms

Nucleic Acids Res.

(1988)

M. Buvoli et al.

Alternative splicing in the human gene for the core protein A1 generates another hnRNP protein

EMBO J.

(1990)

Y.D. Choi et al.

Heterogeneous nuclear ribonucleoproteins: Role in RNA splicing

Science

(1986)

F. Cobianchi et al.

G. Conway et al.

Ribonucleoproteins package 700 nucleotides of pre-mRNA into a repeating array of regular particles

Mol. Cell. Biol.

(1988)

L. Dayley et al.

Purification of the human histone H4 gene-specific transcription factors H4TF-1 and H4TF-2

Genes Dev.

(1988)

G. Dreyfuss

Structure and function of nuclear and cytoplasmic ribonucleoprotein particles

Annu. Rev. Cell Biol.

(1986)

G. Dreyfuss et al.

hnRNP proteins and the biogenesis of mRNA

Annu. Rev. Biochem.

(1993)

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SUMOylation of HNRNPA2B1 modulates RPA dynamics during unperturbed replication and genotoxic stress responses
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Replication protein A (RPA) is a major regulator of eukaryotic DNA metabolism involved in multiple essential cellular processes. Maintaining appropriate RPA dynamics is crucial for cells to prevent RPA exhaustion, which can lead to replication fork breakage and replication catastrophe. However, how cells regulate RPA availability during unperturbed replication and in response to stress has not been well elucidated. Here, we show that HNRNPA2B1^SUMO functions as an endogenous inhibitor of RPA during normal replication. HNRNPA2B1^SUMO associates with RPA through recognizing the SUMO-interacting motif (SIM) of RPA to inhibit RPA accumulation at replication forks and impede local ATR activation. Declining HNRNPA2^SUMO induced by DNA damage will release nuclear soluble RPA to localize to chromatin and enable ATR activation. Furthermore, we characterize that HNRNPA2B1 hinders homologous recombination (HR) repair via limiting RPA availability, thus conferring sensitivity to PARP inhibitors. These findings establish HNRNPA2B1 as a critical player in RPA-dependent surveillance networks.
Structural Insight Into hnRNP A2/B1 Homodimerization and DNA Recognition
2023, Journal of Molecular Biology
Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) has been identified as a nuclear DNA sensor. Upon viral infection, hnRNP A2/B1 recognizes pathogen-derived DNA as a homodimer, which is a prerequisite for its translocation to the cytoplasm to activate the interferon response. However, the DNA binding mechanism inducing hnRNP A2/B1 homodimerization is unknown. Here, we show the crystal structure of the RNA recognition motif (RRM) of hnRNP A2/B1 in complex with a U-shaped ssDNA, which mediates the formation of a newly observed protein dimer. Our biochemical assays and mutagenesis studies confirm that the hnRNP A2/B1 homodimer forms in solution by binding to pre-generated ssDNA or dsDNA with a U-shaped bulge. These results depict a potential functional state of hnRNP A2/B1 in antiviral immunity and other cellular processes.
Emerging roles of hnRNP A2B1 in cancer and inflammation
2022, International Journal of Biological Macromolecules
Citation Excerpt :
In mice, the hnRNP A2B1 gene forms four variants through alternative splicing, namely, A2 (excluding exon 2), B1 (including all exons), A2b (excluding exons 2 and 9), and B1b (excluding exon 9) [33]. Human cells mainly express A2 and B1 proteins (341 and 353 amino acids, respectively), both of which are similar in structure and are highly homologous [34,35]. Both isoforms have an RNA-binding domain (RBD) composed of two tandem RNA recognition motifs (RRMs) separated by a 15-aa linker, a C-terminal Gly-rich low complexity (LC) region that includes a prion-like domain (PrLD), an RGG box, and a PY motif that contains an M9 nuclear localization signal (PY-NLS) [36–40] (Fig. 1).
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a group of RNA-binding proteins with important roles in multiple aspects of nucleic acid metabolism, including the packaging of nascent transcripts, alternative splicing, transactivation of gene expression, and regulation of protein translation. As a core component of the hnRNP complex in mammalian cells, heterogeneous nuclear ribonucleoprotein A2B1 (hnRNP A2B1) participates in and coordinates various molecular events. Given its regulatory role in inflammation and cancer progression, hnRNP A2B1 has become a novel player in immune response, inflammation, and cancer development. Concomitant with these new roles, a surprising number of mechanisms deemed to regulate hnRNP A2B1 functions have been identified, including post-translational modifications, changes in subcellular localization, direct interactions with multiple DNAs, RNAs, and proteins or the formation of complexes with them, which have gradually made hnRNP A2B1 a molecular target for multiple drugs. In light of the rising interest in the intersection between cancer and inflammation, this review will focus on recent knowledge of the biological roles of hnRNP A2B1 in cancer, immune response, and inflammation.
Heterogeneous nuclear ribonucleoprotein A2/B1 is a negative regulator of human breast cancer metastasis by maintaining the balance of multiple genes and pathways
2020, EBioMedicine
Heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 is an important RNA-binding protein that affects the RNA processing, splicing, transport and stability of many genes. hnRNPA2/B1 is expressed during proliferation and metastasis of various cancer types and promotes such processes. However, the precise role and mechanism of hnRNPA2/B1 in breast cancer remain unclear.
The association of hnRNPA2/B1 with breast cancer metastasis was assessed using tissue chips, mouse models and publicly available data. The role and mechanism of hnRNPA2/B1 in breast cancer metastasis were studied in cell lines and mouse models.
In contrast to other cancer research findings, hnRNPA2/B1 expression was negatively correlated with breast cancer metastasis. hnRNPA2/B1 inhibited MDA-MB-231 triple-negative breast cancer (TNBC) cell metastasis in vitro and in vivo. hnRNPA2/B1 knockout activated ERK-MAPK/Twist and GR-beta/TCF4 pathways but inhibited STAT3 and WNT/TCF4 signalling pathways. Profilin 2 (PFN2) promoted breast cancer cell migration and invasion, whereas hnRNPA2/B1 bound directly to the UAGGG locus in the 3′-untranslated region of PFN2 mRNA and reduced the stability of PFN2 mRNA.
Our data supported the role of hnRNPA2/B1 in tumour metastasis risk and survival prediction in patients with breast cancer. The inhibitory role of hnRNPA2/B1 in metastasis was a balance of downstream multiple genes and signalling pathways. PFN2 downregulation by hnRNPA2/B1 might partly explain the inhibitory mechanism of hnRNPA2/B1 in breast cancer metastasis. Therefore, hnRNPA2/B1 might be used as a new prognostic biomarker and valuable molecular target for breast cancer treatments.
DjhnRNPA2/B1-like gene is required for planarian regeneration and tissue homeostasis
2017, Gene
Citation Excerpt :
Correlated with these diverse structural features, hnRNP proteins have a multitude of cellular functions, such as pre-mRNA splicing, mRNA stability, localization, nucleo-cytoplasmic export, DNA replication and repair and telomere maintence. Two important members of hnRNPs, hnRNPA2 and hnRNPB1, which are generally considered from the same origin after splicing variant insertion and formation because of similar structures and highly homologous (Kozu et al., 1995). In Homo sapiens, compared with hnRNPA2, the cDNA sequence of hnRNPB1 gene only inserts a 36 bp nucleotide fragment at 5 'end and a 12 amino acid stretches present near the amino terminus of hnRNPA2, and therefore they are collectively called hnRNPA2/B1.
The hnRNPs play important roles in physiological processes in eukaryotic organisms by regulation of pre-mRNA after transcription, including pre-mRNA splicing, mRNA stability, DNA replication and repair and telomere maintenance and so on. However, it remains unclear about the specific functions of these genes. In this study, the full-length cDNA sequence of hnRNPA2/B1-like was first cloned from Dugesia japonica, and its roles were investigated by WISH and RNAi. The results showed that: (1) DjhnRNPA2/B1-like was highly conserved during animal evolution; (2) DjhnRNPA2/B1-like mRNA was mainly distributed each side of the body in intact worms and regenerative blastemas, and its expression levels were up-regulated on days 0 and 5 after amputation; (3) the intact and regenerating worms gradually lysed or lost regeneration capacity after DjhnRNPA2/B1-like RNAi; and (4) DjhnRNPA2/B1-like expression is induced by temperature and heavy metal ion stress. The data suggests that DjhnRNPA2/B1-like is a multiple functional gene, it plays important roles in regeneration and homeostatic maintenance and it is also involved in stress responses in planarians. Our work provides basic data for the study of regenerative mechanism and stress responses in freshwater planarians.
HnRNP A2/B1 interacts with influenza A viral protein NS1 and inhibits virus replication potentially through suppressing NS1 RNA/protein levels and NS1 mRNA nuclear export
2014, Virology
Citation Excerpt :
In the present study, through a 2-DE-based proteomic approach, we found that NS1 is associated with hnRNP A2/B1, a member of a large family of proteins that are highly divergent in structure and function (Han et al., 2010; Shyu and Wilkinson, 2000). hnRNP A2 and B1 proteins are produced by alternative splicing of a single gene with the difference of a 12-amino-acid insertion in N-terminal RNA-binding motif in B1 (Burd et al., 1989; Kozu et al., 1995) and have been shown to regulate RNA alternative splicing (Bilodeau et al., 2001; Mayeda et al., 1994), RNA trafficking (Munro et al., 1999; Pinol-Roma and Dreyfuss, 1992; Shan et al., 2003), and telomere maintenance (Ford et al., 2002). Most cellular mRNAs are transported from the nucleus to the cytoplasm through the mRNA export receptors Tap/NXF1 that interact with both mRNAs and components of the nuclear pore complex to direct mRNAs through the nuclear pore complex (Stutz and Izaurralde, 2003).
The NS1 protein of influenza viruses is a major virulence factor and exerts its function through interacting with viral/cellular RNAs and proteins. In this study, we identified heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) as an interacting partner of NS1 proteins by a proteomic method. Knockdown of hnRNP A2/B1 by small interfering RNA (siRNA) resulted in higher levels of NS vRNA, NS1 mRNA, and NS1 protein in the virus-infected cells. In addition, we demonstrated that hnRNP A2/B1 proteins are associated with NS1 and NS2 mRNAs and that knockdown of hnRNP A2/B1 promotes transport of NS1 mRNA from the nucleus to the cytoplasm in the infected cells. Lastly, we showed that knockdown of hnRNP A2/B1 leads to enhanced virus replication. Our results suggest that hnRNP A2/B1 plays an inhibitory role in the replication of influenza A virus in host cells potentially through suppressing NS1 RNA/protein levels and NS1 mRNA nucleocytoplasmic translocation.

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^☆: The nucleotide sequence data reported in this paper have been deposited with the GSDB, DDBJ, EMBL, and NCBI nucleotide sequence databases under Accession No. D28877.

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Structure and expression of the gene (HNRPA2B1) encoding the human hnRNP protein A2/B1☆

Abstract

J. Mol. Biol.

Cell

J. Mol. Biol.

J. Mol. Biol.

Anal. Biochem.

J. Biol. Chem.

Prog. Nucleic Acid Res. Mol. Biol.

Int. Rev. Cytol.

Cell

The core proteins A2 and B1 exist as (A2)3B1 tetramers in 40S nuclear ribonucleoprotein particles

Mol. Cell. Biol.

Primary structures of the heterogeneous nuclear ribonucleoprotein A2, B1, and C2 proteins: A diversity of RNA binding proteins is generated by small peptide inserts

Proc. Natl. Acad. Sci. USA

cDNA cloning of human hnRNP protein A1 reveals the existence of multiple mRNA isoforms

Nucleic Acids Res.

Alternative splicing in the human gene for the core protein A1 generates another hnRNP protein

EMBO J.

Heterogeneous nuclear ribonucleoproteins: Role in RNA splicing

Science

Ribonucleoproteins package 700 nucleotides of pre-mRNA into a repeating array of regular particles

Mol. Cell. Biol.

Purification of the human histone H4 gene-specific transcription factors H4TF-1 and H4TF-2

Genes Dev.

Structure and function of nuclear and cytoplasmic ribonucleoprotein particles

Annu. Rev. Cell Biol.

hnRNP proteins and the biogenesis of mRNA

Annu. Rev. Biochem.