Alternative splicing in the human gene for the core protein A1 generates another hnRNP protein.
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.
Istituto di Genetica Biochimica ed Evoluzionistica CNR, Pavia, Italy.
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Buvoli
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Cobianchi
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Bestagno
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Mangiarotti
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Bassi
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Biamonti
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Riva
D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D003001:Cloning, Molecular; D004273:DNA, Neoplasm / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005091:Exons; D005796:Genes; D006367:HeLa Cells / Q000378:metabolism; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D011061:Poly A / Q000235:genetics / Q000302:isolation & purification; D014176:Protein Biosynthesis; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012326:RNA Splicing; D012332:RNA, Heterogeneous Nuclear / Q000235:genetics*; D012333:RNA, Messenger; D012261:Ribonucleoproteins / Q000235:genetics*; D014158:Transcription, Genetic
D004273:DNA, Neoplasm; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D015345:Oligonucleotide Probes; D012332:RNA, Heterogeneous Nuclear; D012333:RNA, Messenger; D012261:Ribonucleoproteins; D011061:Poly A; D012313:RNA