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Sequence analysis of the cloned mRNA coding for glyceraldehyde-3-phosphate dehydrogenase from chicken heart muscle
Abstract:
Using a cloned cDNA (pGAP30) the nucleotide sequence for chicken glyceraldehyde-3-phosphate dehydrogenase mRNA has been determined. The cDNA insert contains 1051 nucleotides representing the amino acid coding sequence, with the exception of 49 NH2-terminal amino acids, and includes the entire 3'-noncoding region. Sequence information on the missing 5' terminus of the mRNA, not represented in the clone pGAP30, was obtained by extension of the cDNA using an 85-nucleotide-long internal fragment as a primer. Thus the sequence of 310 amino acids of chicken glyceraldehyde-3-phosphate dehydrogenase representing 93% of the complete primary structure could be derived. The coding portion exhibits non-random utilization of synonymous codons with a strong bias for codons with G or C at the third position. The non-coding region contains several octanucleotides which are repeated and shows a potentially stable stem-and-loop structure located towards the end of the mRNA. Hypothetical functional implications of the putative secondary structure are discussed.
Insights
Researchers sequenced chicken glyceraldehyde-3-phosphate dehydrogenase mRNA, revealing 93% of the primary structure. Analysis showed non-random codon usage and a stable stem-loop in the 3' non-coding region.
Area of Science:
- Molecular Biology
- Biochemistry
- Genomics
Background:
- Chicken glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key enzyme in glycolysis.
- Understanding its mRNA sequence provides insights into gene expression and regulation.
Purpose of the Study:
- To determine the complete nucleotide sequence of chicken GAPDH mRNA.
- To analyze codon usage bias and non-coding regions for functional implications.
Main Methods:
- Cloning of chicken GAPDH cDNA (pGAP30).
- Nucleotide sequencing using Sanger sequencing.
- 5' end cDNA extension using an internal fragment primer.
Main Results:
- Determined 1051 nucleotides of the coding sequence and the entire 3'-noncoding region.
- Derived the sequence for 310 amino acids (93% of the primary structure).
- Observed non-random synonymous codon utilization with a G/C bias at the third position.
- Identified repeated octanucleotides and a potential stem-loop structure in the 3'-noncoding region.
Conclusions:
- The derived chicken GAPDH mRNA sequence provides a comprehensive genetic blueprint.
- Codon usage patterns suggest evolutionary selection pressures.
- The 3'-noncoding region's secondary structure may play a role in mRNA stability or translation regulation.