| 2008 |
hnRNPLL was identified as a critical inducible regulator of CD45 alternative splicing in T cells. It is up-regulated upon T cell stimulation, binds CD45 pre-mRNA transcripts, and is both necessary and sufficient for activation-induced skipping of CD45 variable exons (generating the CD45RO isoform from CD45RA). Depletion or overexpression in B and T cell lines and primary T cells reciprocally altered CD45RA and RO expression. Exon array analysis indicated hnRNPLL acts as a global regulator of alternative splicing in activated T cells. |
shRNA interference screen, overexpression, RNA binding assays, exon array analysis, flow cytometry for CD45 isoforms |
Science |
High |
18669861
|
| 2008 |
A single point mutation in hnRNPLL destabilizes its RNA-recognition domain, which normally binds with micromolar affinity to RNA containing the Ptprc (CD45) exon-silencing sequence. This mutation selectively diminished T cell accumulation in peripheral lymphoid tissues without affecting proliferation, and abrogated the extensive program of alternative mRNA splicing in memory T cells coordinated by hnRNPLL. |
ENU mutagenesis screen, RRM domain binding assay (micromolar affinity measurement), exon-array analysis of mutant naive and memory T cells |
Immunity |
High |
19100700
|
| 2008 |
hnRNP LL (hnRNPLL) was identified via a cell-based screen as a distinct signal-induced repressor of CD45 variable exon 4. Its expression and binding to the ESS1 exonic splicing silencer element are up-regulated upon T cell activation. hnRNPLL overexpression increases exon repression; knockdown eliminates activation-induced exon skipping. hnRNPLL has overlapping but distinct binding requirements compared to hnRNP L at ESS1. |
Cell-based screen for splicing regulators, microarray, overexpression, knockdown, RNA-protein binding assays with ESS1 mutants |
RNA |
High |
18719244
|
| 2012 |
In plasma cells, hnRNPLL binds Ighg2b mRNA transcripts and promotes an increase in membrane-encoding Ighg2b isoform at the expense of the secreted isoform (opposing ELL2 function). hnRNPLL also alters splicing of CD44 pre-mRNA in plasma cells, promoting variable exon inclusion and decreasing overall CD44 expression. |
lentiviral shRNA screen, transcriptional profiling, RNA immunoprecipitation, RNA-Seq, isoform-specific RT-PCR |
PNAS |
High |
22991471
|
| 2014 |
hnRNPLL induces retention of specific introns in polyadenylated mRNA, including introns flanking variable exons 4–6 of Ptprc (CD45). In T cells with an inactivating Hnrpll mutation, these introns are no longer retained. A similar pattern of hnRNPLL-induced differential intron retention flanking alternative exons was identified in 14 other genes. Retroviral re-expression of a normally spliced cDNA of one target, Senp2, partially rescued the survival defect of Hnrpll-mutant T cells, placing Senp2 downstream of hnRNPLL. |
Deep sequencing of polyadenylated RNA from Hnrpll-mutant T cells and B cells with low Hnrpll; retroviral rescue experiment |
Genome Biology |
High |
24476532
|
| 2015 |
hnRNPLL preferentially recognizes CA dinucleotide-containing sequences in introns and 3' UTRs of target RNAs in plasma cells (identified by PAR-CLIP). It promotes exon inclusion or exclusion in a context-dependent manner and stabilizes mRNA when associated with 3' UTRs. During B cell to plasma cell differentiation, hnRNPLL mediates a genome-wide switch of RNA processing, leading to loss of Bcl6 expression and increased Ig production. |
PAR-CLIP (Photoactivatable-Ribonucleoside-Enhanced Cross-Linking and Immunoprecipitation), RNA sequencing, primary B cell to plasma cell differentiation assay |
PNAS |
High |
25825742
|
| 2017 |
hnRNPLL specifically associates with cytoplasmic poly(A)-binding protein PABPC1 in both T cells and plasma cells (co-immunoprecipitation). PABPC1 is not required for hnRNPLL-mediated alternative splicing of CD45, but promotes hnRNPLL binding to immunoglobulin mRNA and regulates switching from membrane IgH to secreted IgH, likely via mRNA alternative polyadenylation. |
Co-immunoprecipitation, RNA immunoprecipitation, isoform-specific RT-PCR, knockdown of PABPC1 |
Journal of Biological Chemistry |
Medium |
28611064
|
| 2017 |
HNRNPLL knockdown enhanced invasion activity of colon cancer cells in vitro and metastatic ability in vivo. RNA immunoprecipitation showed HNRNPLL binds CD44 pre-mRNA; knockdown increased CD44 variable exon 6 (Cd44v6) levels, and a neutralizing CD44v6 antibody suppressed the invasion induced by HNRNPLL knockdown. HNRNPLL expression was down-regulated during EMT, defining a HNRNPLL–CD44v6 axis in colorectal cancer metastasis suppression. |
Genome-wide shRNA library screen in vivo (rectal implantation syngeneic mouse model), RNA immunoprecipitation, Matrigel invasion assay, neutralizing antibody rescue |
Gut |
High |
28360095
|
| 2018 |
An alternative HNRNPLL transcript variant containing an additional exon 12A (E12A) is generated by ADAR1/ADAR2-mediated A-to-I RNA editing. ADAR editing of exon 12A creates an enhancer for the splicing factor SRSF1, thereby promoting inclusion of E12A via splicing. The E12A isoform regulates a distinct set of growth-related genes (including CCND1 and TGFBR1) compared to canonical HNRNPLL; silencing E12A impairs clonogenic ability and enhances sensitivity to doxorubicin. |
RNA-seq, ADAR knockdown/overexpression, splicing reporter assays, SRSF1 binding analysis, clonogenic assay, drug sensitivity assay |
Journal of Biological Chemistry |
Medium |
29769310
|
| 2018 |
HNRNPLL stabilizes mRNAs encoding DNA replication factors PCNA, RFC3, and FEN1 in colorectal cancer cells, promoting cell cycle progression and proliferation. RNA immunoprecipitation demonstrated direct binding of HNRNPLL to these mRNAs. HNRNPLL overexpression suppressed actinomycin D-induced degradation of these transcripts, and knockdown of any single target (PCNA, RFC3, or FEN1) suppressed the proliferative effect of HNRNPLL overexpression. |
RNA immunoprecipitation, actinomycin D mRNA stability assay, RNA-seq, knockdown epistasis experiments, cell proliferation assay |
Cancer Science |
Medium |
29869816
|
| 2020 |
hnRNPLL controls exit from pluripotency in embryonic stem cells by promoting ES cell-preferred exon skipping events upon onset of differentiation. hnRNPLL depletion leads to sustained expression of ES cell-preferred isoforms of Bptf and Tbx3, causing differentiation deficiency, developmental defects, and growth impairment in hnRNPLL-KO mice. |
Bioinformatic screening combined with functional RBP knockdown/knockout, alternative splicing analysis by RNA-seq, hnRNPLL knockout mice |
The EMBO Journal |
High |
33349972
|
| 2011 |
hnRNPLL acts as a trans-acting factor required for alternative splicing of the Ptprc mRNA (silencing of CD45 RA, RB, and RC exons) in both conventional T cells and NKT cells equally. However, hnRNPLL is required for survival of conventional T cells but not NKT cells, revealing divergent functions beyond splicing regulation. |
Analysis of Hnrpllthunder point mutation in mice, flow cytometry, CD45 isoform analysis by RT-PCR, cell number and functional assays in NKT vs conventional T cells |
PLoS ONE |
Medium |
22073166
|
| 2021 |
In plasmablasts, hnRNPLL mutation disrupts alternative splicing of Ptprc, preventing downregulation of B220 (high-molecular-weight CD45 isoforms persist). However, this dysregulation of Ptprc splicing does not affect B cell development, mature B cell subsets, B cell proliferation, or in vitro plasmablast generation. The germinal center B cell defect in Hnrnpllthu/thu mice is B cell extrinsic. |
Mixed bone marrow chimera analysis, in vitro B cell stimulation and differentiation assays, CD45 isoform analysis, immunization experiments |
Immunology and Cell Biology |
Medium |
33331104
|
| 2023 |
A lncRNA (lnc-PPP2R1B) physically interacts with and stabilizes HNRNPLL protein. This interaction promotes HNRNPLL-mediated alternative splicing of PPP2R1B pre-mRNA, retaining exons 2 and 3, which preserves PP2A enzyme function, enhances dephosphorylation and nuclear translocation of β-catenin, and thereby promotes osteogenesis of mesenchymal stem cells. |
RNA immunoprecipitation, lncRNA overexpression/knockdown, HNRNPLL knockdown, alternative splicing analysis, PP2A activity assay, β-catenin nuclear translocation assay, in vivo ectopic osteogenesis |
Stem Cell Reviews and Reports |
Medium |
37243830
|
| 2024 |
hnRNPLL regulates alternative splicing of myoferlin (MYOF) pre-mRNA in pancreatic ductal adenocarcinoma. hnRNPLL depletion stimulates MYOF exon 17 retention, reducing production of the short MYOF isoform (MYOFb) and inhibiting cancer cell migration and invasion. Overexpression of hnRNPLL or MYOFb promoted pancreatic cancer cell migration and invasion, placing MYOFb downstream of hnRNPLL in promoting early metastasis. |
RNA-seq (exon skipping analysis), hnRNPLL knockdown/overexpression, MYOFb overexpression rescue, migration and invasion assays |
Cancer Letters |
Medium |
39742990
|