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AFP anti‐sense transcripts in mouse liver and their potential role in gene regulation
Author(s) -
Dixon Maria S.,
Qiu Guofang,
Spear Brett T.,
Peterson Martha L.
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.804.4
Subject(s) - biology , gene , messenger rna , exon , gene expression , liver cancer , hepatocellular carcinoma , rna , regulation of gene expression , long non coding rna , cancer research , microbiology and biotechnology , genetics
Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer, ranking the sixth most common cancer and third most common cause of cancer mortality worldwide. We have been studying mouse liver gene regulation to better understand mechanisms by which changes in gene expression contribute to liver development, homeostasis and disease. We identified Zinc Fingers and Homeoboxes 2 (Zhx2) as a regulator of alpha‐fetoprotein (AFP), a plasma protein that is highly expressed in the fetal liver but is shut off after birth. AFP expression is elevated in regenerating adult liver and hepatocellular carcinoma (HCC) and has been used extensively as a diagnostic marker of liver cancer. Interestingly, all genes that are misregulated in the absence of Zhx2 are also misregulated in HCC. Thus, to better understand gene regulation during HCC, we have been studying of the mechanism by which Zhx2 regulates gene expression. While studying AFP mRNA regulation by Zhx2, we identified previously unannotated antisense transcripts (asAFP) that partially overlap the 3′ half of the mouse AFP gene. asAFP RNAs are ~5kb alternatively spliced, mainly cytoplasmic, transcripts containing 2–4 exons that are likely to be non‐coding RNAs. These antisense transcripts were also detected in mouse liver RNA‐seq data. The abundance of asAFP RNA inversely correlates with AFP mRNA levels during postnatal development. Normally, asAFP RNA levels are high and AFP mRNA levels are low in the adult mouse liver. However, in the absence of Zhx2, AFP mRNA levels are higher and asAFP RNA levels are reduced. When portions of the asAFP RNA are over‐expressed in a liver cell line, endogenous AFP mRNA was reduced, suggesting asAFP transcripts repress AFP mRNA expression in trans. We will also knock‐down asAFP RNA and predict that AFP mRNA levels will increase. My central hypothesis is that asAFP RNA contributes to the post‐transcriptional regulation of AFP mRNA through an RNA‐RNA interaction. We are designing experiments to test this hypothesis and to determine at what level the regulation may occur. Support or Funding Information MCB‐1158234 from the National Science Foundation, R01‐DK59866 from the National Institutes of Health