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Characterization of a complementary deoxyribonucleic acid coding for the gamma chain of human fibrinogen
Abstract:
A number of cDNAs coding for the gamma chain of human fibrinogen have been isolated from a liver cDNA library by employing a synthetic nucleotide mixture as a probe. One of the positive clones was then employed to screen the entire cDNA library of 18000 recombinants, yielding 320 positive clones for the gamma chain. The largest cDNA was 1638 base pairs in length and contained 10 base pairs of poly(G) at the 5'-end followed by 71 base pairs of noncoding nucleotides. The next 78 base pairs coded for a leader sequence that was 26 amino acids in length and included a methionine start signal and a typical hydrophobic core. The following 1233 base pairs coded for 411 amino acids that are present in the mature protein followed by a stop codon of TAA, 207 base pairs of noncoding nucleotides, a poly(A) track of 15 base pairs, and 22 base pairs of poly(C). Specific regions of the cDNA of the gamma chain were then compared with the cDNAs for the alpha and beta chains of human fibrinogen.
Insights
Researchers isolated complementary DNAs (cDNAs) for the human fibrinogen gamma chain from a liver library. This study characterized the gamma chain cDNA, aiding in understanding fibrinogen structure and function.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Fibrinogen is a key protein in blood coagulation.
- Understanding fibrinogen subunit gene structure is crucial for studying its function and related disorders.
Purpose of the Study:
- To isolate and characterize complementary DNAs (cDNAs) encoding the gamma chain of human fibrinogen.
- To compare the gamma chain cDNA with those of alpha and beta chains.
Main Methods:
- Screening of a liver cDNA library using a synthetic nucleotide probe.
- Isolation and sequencing of positive clones.
- Comparative analysis of nucleotide sequences.
Main Results:
- Isolation of numerous positive clones for the gamma chain cDNA.
- Characterization of the largest cDNA, including its length (1638 bp), non-coding regions, leader sequence, and mature protein coding sequence.
- Identification of a stop codon, poly(A) track, and poly(C) sequence.
- Comparison of gamma chain cDNA regions with alpha and beta chain cDNAs.
Conclusions:
- Successful isolation and detailed characterization of human fibrinogen gamma chain cDNA.
- Provides a foundation for further studies on fibrinogen structure-function relationships and genetic variations.