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[mRNA localization and content in bovine kininogen]
Abstract:
The bradykinin (BK) gene chemically synthesized and cloned into pBR 322 was used for the study of tissue localization and quantitation of mRNA coding for the BK precursor, kininogen. Poly(A+)-mRNAs from bovine liver, spleen, kidney, mammary gland and pancreas were used for dot-hybridization to [32P]DNA of the BK gene or to the plasmid-containing BK gene. The experimental results demonstrate that [32P]DNA of BK is hybridized only to the liver poly(A+)-RNA, which proves the liver to be the main kininogen mRNA-producing tissue. In other tissues, the kininogen mRNA synthesis is either altogether absent or its level is two orders of magnitude less as compared to the liver. Several approaches for the quantitation of the kininogen mRNA were developed. The amount of this mRNA was shown to be about 0.6% of the total cellular poly(A+)-RNA. Poly(A+)-RNA which is bound to BK DNA-cellulose and is enriched with BK-coding sequences was used for the study of the hybridization kinetics and translation in a cell-free system from rabbit reticulocytes. The polypeptides synthesized contain BK as was shown by the use of a bio-test in rat uterus.
Insights
The liver is the primary site for producing kininogen messenger RNA (mRNA), which codes for the bradykinin (BK) precursor. This mRNA is largely absent or present at very low levels in other bovine tissues.
Area of Science:
- Molecular Biology
- Biochemistry
Context:
- Bradykinin (BK) is a peptide hormone with significant physiological roles.
- Understanding the tissue-specific production of its precursor, kininogen, is crucial for comprehending BK regulation.
Purpose:
- To investigate the tissue localization and quantity of kininogen mRNA in bovine tissues.
- To identify the primary tissue responsible for kininogen mRNA synthesis.
Summary:
- Chemically synthesized bradykinin (BK) gene was used to study kininogen mRNA localization and quantitation.
- Dot-hybridization experiments using [32P]DNA of the BK gene revealed that only liver poly(A+)-RNA hybridized, indicating the liver as the main kininogen mRNA-producing tissue.
- Kininogen mRNA levels in other tissues were negligible compared to the liver, representing approximately 0.6% of total cellular poly(A+)-RNA.
Impact:
- Establishes the liver as the predominant site for kininogen mRNA synthesis.
- Provides quantitative data on kininogen mRNA levels.
- Facilitates further research into bradykinin biosynthesis and regulation.