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C L Gray

Publications and source records attributed to C L Gray.

24 records · Page 2Linked to original sources

Assaying the quality of cDNA libraries.

Once a cDNA library has been constructed, it is very useful to be able to easily assess the quality of the library. Because actin is a ubiquitous sequence, this assessment has been accomplished by probing filter lifts and Southern blots of libraries with an actin cDNA probe. These methods provide information about the percent of actin-positive clones and the degree of completeness of cDNA clones in a library. Results of these methods are correlated with the success of finding full-length clones of interest.

Actins↗

Nucleotide sequence of the gene coding for human factor VII, a vitamin K-dependent protein participating in blood coagulation.

Activated factor VII (factor VIIa) is a vitamin K-dependent plasma serine protease that participates in a cascade of reactions leading to the coagulation of blood. Two overlapping genomic clones containing sequences encoding human factor VII were isolated and characterized. The complete sequence of the gene was determined and found to span about 12.8 kilobases. The mRNA for factor VII as demonstrated by cDNA cloning is polyadenylylated at multiple sites but contains only one AAUAAA poly(A) signal sequence. The mRNA can undergo alternative splicing, forming one transcript containing eight segments as exons and another with an additional exon that encodes a larger prepro leader sequence. The latter transcript has no known counterpart in the other vitamin K-dependent proteins. The positions of the introns with respect to the amino acid sequence encoded by the eight essential exons of factor VII are the same as those present in factor IX, factor X, protein C, and the first three exons of prothrombin. These exons code for domains generally conserved among members of this gene family. The comparable introns in these genes, however, are dissimilar with respect to size and sequence, with the exception of intron C in factor VII and protein C. The gene for factor VII also contains five regions made up of tandem repeats of oligonucleotide monomer elements. More than a quarter of the intron sequences and more than a third of the 3' untranslated portion of the mRNA transcript consist of these minisatellite tandem repeats.

Base Sequence↗

Characterization of a cDNA coding for human factor VII.

Factor VII is a precursor to a serine protease that is present in mammalian plasma. In its activated form, it participates in blood coagulation by activating factor X and/or factor IX in the presence of tissue factor and calcium. Clones coding for factor VII were obtained from two cDNA libraries prepared from poly(A) RNA from human liver and Hep G2 cells. The amino acid sequence deduced from the cDNAs indicates that factor VII is synthesized with a prepro-leader sequence of 60 or 38 amino acids. The mature protein that circulates in plasma is a single-chain polypeptide composed of 406 amino acids. The amino acid sequence analysis of the protein and the amino acid sequence deduced from the cDNAs indicate that factor VII is converted to factor VIIa by the cleavage of a single internal bond between arginine and isoleucine. This results in the formation of a light chain (152 amino acids) and a heavy chain (254 amino acids) that are held together by a disulfide bond. The light chain contains a gamma-carboxyglutamic acid (Gla) domain and two potential epidermal growth factor domains, while the heavy chain contains the serine protease portion of the molecule. Factor VII shows a high degree of amino acid sequence homology with the other vitamin K-dependent plasma proteins.

Amino Acid Sequence↗

Interstitial pregnancy.

A case of ruptured interstitial pregnancy is reported, along with review of the literature. Although sonography did not differentiate between interstitial and intrauterine pregnancy, I believe it will prove to be one of the most accurate diagnostic aids in detecting this condition.

Adult↗

Ovarian pregnancy associated with intrauterine contraceptive devices.

Four cases of ovarian pregnancy, occurring over a two-year period in the same hospital, are presented. Each case fulfills Spiegelberg's criteria. Each patient conceived with Cu-7 intrauterine contraceptive device (IUD) in situ. Review of the literature reveals an apparent increase in the frequency of ovarian pregnancy associated with IUD's. This aspect of the problem, as well as the management of this unusual type of ectopic pregnancy, is discussed. The data available do not justify a conclusion that ovarian pregnancies are caused by IUD's. Unless future studies demonstrate a cause-and-effect relationship, this may be merely an interesting coincidence. However, it seems that more than just coincidence is involved, even though the mechanism is unclear.

Chorion↗