Student Theses and Dissertations

Date of Award

1985

Document Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Abstract

Assays of transcription rate and mRNA concentration were designed and employed to measure the production of a series of liver-specific and common mRNAs in fresh livers, primary hepatocyte cultures, and hepatoma cell lines, derived from mice or rats. The transcription rates of many different liver-specific but no common mRNAs were found to decline sharply within 24 hours when hepatocytes from the liver were explanted and placed into primary culture. Hepatoma cells known to display liver-specific characteristics also transcribed liver-specific genes at low levels similar to primary cultured hepatocytes. In contrast, slices of liver tissue exposed to the same culture conditions for 24 hours maintained high rates of liver-specific transcription. These and other experiments demonstrate that: 1) maximum transcription of many liver-specific mRNAs depends on the maintenance of the cells in a mature tissue structure; 2) low levels of liver-specific mRNA production can persist outside the tissue, and 3) the coordinate loss and recovery of many different liver functions observed in one line of hepatoma cell clones involve the regulation of tissue-specific mRNA concentrations through both transcriptional and posttranscriptional means.

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