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Sequence of the murine alpha-lactalbumin-encoding cDNA: interspecies comparison of the coding frame and deduced
J L Vilotte1, S Soulier, J C Mercier
1Laboratoire de Génétique Biochimique, INRA-CRJ, Jouy-en-Josas, France.
Abstract:
The structure of the mouse alpha-lactalbumin-encoding mRNA was deduced from sequence analysis of eight cDNA clones. The almost full-length mRNA of 732 nucleotides [poly(A) tail excluded] and the deduced pre-protein share 85% and 86% homology with their rat counterpart, respectively. Interspecies comparison of the pre-protein showed the occurrence of an extra amino acid (aa) in the signal peptide and of two mutations affecting two reported invariant aa residues at positions 44 and 107, which weakens the assumption that both aa residues might play a significant structural and/or functional role.
Insights
Mouse alpha-lactalbumin mRNA structure was determined via cDNA sequencing. Comparison with rat revealed minor differences in the pre-protein, questioning the significance of invariant amino acid residues.
Area of Science:
- Molecular Biology
- Genomics
- Biochemistry
Background:
- Alpha-lactalbumin is a key protein in milk production.
- Understanding its genetic structure is crucial for comparative studies.
Purpose of the Study:
- To determine the complete mRNA structure of mouse alpha-lactalbumin.
- To compare the mouse sequence with its rat counterpart.
Main Methods:
- Sequence analysis of eight cDNA clones.
- Deduction of mRNA and pre-protein sequences.
- Interspecies sequence comparison.
Main Results:
- The mouse alpha-lactalbumin mRNA is 732 nucleotides long (excluding poly(A) tail).
- Mouse pre-protein shows 86% homology with rat pre-protein.
- Identified an extra amino acid in the signal peptide and two mutations in conserved residues.
Conclusions:
- The deduced mouse alpha-lactalbumin pre-protein sequence has minor variations compared to rat.
- These variations challenge the presumed structural or functional importance of invariant amino acid residues at positions 44 and 107.