Heterogeneous nuclear ribonucleoproteins F and H/H' show differential expression in normal and selected cancer tissues.
The heterogeneous nuclear ribonucleoproteins (hnRNPs) F and H/H', containing the quasi-RNA recognition motif (qRRM) domains, are implicated in several steps of pre-mRNA processing and in cellular differentiation. We have compared a set of tissues and found striking differences in their levels of expression as well as in the nuclear versus the cytoplasmic distribution. Generally, hnRNP F is broadly expressed in many tissues with extremely strong expression in the prostate gland while hnRNP H/H' shows a more restricted degree of expression with low expression in some tissues, for example, liver, exocrine acini of the pancreas, thyroid gland and heart. At the cellular level, hnRNP F is, with few exceptions, predominantly expressed in the cytoplasm while hnRNP H/H' is more abundant in the nuclei. A quite pronounced heterogeneous expression pattern is seen in the proximal tubules of the kidney where hnRNP F is present at moderate cytoplasmic levels while hnRNP H/H' is undetectable, whereas both proteins are more evenly expressed in distal tubules and collecting ducts. Generally, tumor tissues reveal a broad expression of hnRNP F in the nuclei as well as in the cytoplasm while hnRNP H/H' is expressed at higher levels in the nuclei than in the cytoplasm. Up-regulation of hnRNP H/H' is found in a few tissues that normally express low cytoplasmic levels of hnRNP H/H', for example, adenocarcinoma of the pancreas, hepatocellular carcinoma and gastric carcinoma. hnRNP F is down-regulated in hepatocellular carcinoma and up-regulated in gastric carcinoma. The present study indicates the important potential role of this subset of hnRNPs on the gene expression in many tissues.
Honoré
Bent
B
Department of Medical Biochemistry, University of Aarhus, DK-8000 Aarhus C, Denmark. bh@biokemi.au.dk
Baandrup
Ulrik
U
Vorum
Henrik
H
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H