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.
Buvoli
M
M
Istituto di Genetica Biochimica ed Evoluzionistica CNR, Pavia, Italy.
Cobianchi
F
F
Bestagno
M G
MG
Mangiarotti
A
A
Bassi
M T
MT
Biamonti
G
G
Riva
S
S
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