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

EMBO J. 1990 Apr;9(4):1229-35.


The human hnRNP core protein A1 (34 kd) is encoded by a 4.6 kb gene split into 10 exons. Here we show that the A1 gene can be differentially spliced by the addition of an extra exon. The new transcript encodes a minor protein of the hnRNP complex, here defined A1B protein, with a calculated mol. wt of 38 kd, that coincides with a protein previously designated as B2 by some authors. In vitro translation of the mRNAs selected by hybridization with A1 cDNA produced two proteins of 34 and 38 kd; Northern blot analysis of poly(A)+ RNA from HeLa cells revealed that the abundance of the A1B mRNA was approximately 5% that of A1. The A1B protein was detected by Western blotting with an anti-A1 monoclonal antibody both in enriched preparations of basic hnRNP proteins and in 40S hnRNP particles. The A1B protein exhibits a significantly higher affinity than A1 for ssDNA. The recombinant A1B protein, expressed in Escherichia coli, shows the same electrophoretic mobility and charge as the cellular one.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Blotting, Western
  • Cloning, Molecular
  • DNA, Neoplasm / genetics
  • Escherichia coli / genetics
  • Exons
  • Genes*
  • HeLa Cells / metabolism
  • Heterogeneous Nuclear Ribonucleoprotein A1
  • Heterogeneous-Nuclear Ribonucleoprotein Group A-B*
  • Heterogeneous-Nuclear Ribonucleoproteins
  • Humans
  • Molecular Sequence Data
  • Oligonucleotide Probes
  • Poly A / genetics
  • Poly A / isolation & purification
  • Protein Biosynthesis
  • RNA / genetics
  • RNA / isolation & purification
  • RNA Splicing*
  • RNA, Heterogeneous Nuclear / genetics*
  • RNA, Messenger
  • Ribonucleoproteins / genetics*
  • Transcription, Genetic


  • DNA, Neoplasm
  • Heterogeneous Nuclear Ribonucleoprotein A1
  • Heterogeneous-Nuclear Ribonucleoprotein Group A-B
  • Heterogeneous-Nuclear Ribonucleoproteins
  • Oligonucleotide Probes
  • RNA, Heterogeneous Nuclear
  • RNA, Messenger
  • Ribonucleoproteins
  • Poly A
  • RNA