Biomedical subjects

G Vogeli

Publications and source records attributed to G Vogeli.

41 records · Page 3Linked to original sources

PubMed1980

Isolation and characterization of genomic DNA coding for alpha 2 type I collagen.

We have isolated and characterized a segment of the chick alpha 2 collagen gene by screening a library of chick genomic fragments using as hybridization probe an alpha 2 collagen cDNA clone. Several clones were isolated and one of them, lambda gCOL 204, was used for further studies. The DNA of lambda gCOL 204 hybridizes to a unique species of mRNA the size of alpha 2 collagen mRNA. This mRNA can be translated into a unique polypeptide which comigrates in SDS-gel electrophoresis with pro-alpha 2 collagen. Electron microscopic analysis by R-loop technique indicates that lambda gCOL 204 contains 7Kb of the alpha 2 collagen gene. This 7 Kb piece constitutes the 3' end of the gene. The same clone also contains 9 Kb of DNA that is immediately adjacent to the 3' end of the alpha 2 collagen gene. The cloned segment of the alpha 2 collagen gene is interrupted by 8 intervening sequences of various lengths. The coding sequences for collagen in this clone add up to approximately 1,800 bp, which correspond to about 1/3 of alpha 2 collagen mRNA. DNA sequence analysis of a small coding segment of lambda g COL 204 reveals a characteristic collagen type sequence which encodes for an amino acid sequence identical to a sequence found in calf alpha 2 collagen. The sequence of this region of the protein has not yet been determined for the chick alpha 2 collagen.

Animals↗

PubMed1980

Correlation between splicing sites within an intron and their sequence complementarity with U1 RNA.

We have determined the nucleotide sequence of two short introns (respectively 215 and 90 nucleotides) in the chick alpha 2-collagen (type I) gene as well as parts of the adjacent exons. For one of these introns we find that the 5' end of U1 RNA is complementary not only to the two ends of the intron but also to one end of the intron and sequences inside this intron. These complementarities predict three potential internal splicing sites. By S1 mapping experiments we find three discrete RNA precursors in which different portions of this intron have been deleted. The sizes of the deleted segments are in good agreement with the location of the predicted splicing points inside the intron. The DNA sequence indicates that removal of one portion of the intron should still allow the subsequent elimination of the rest of the intron and the correct splicing of the coding segments located at each end of the intron. The new introns created by the first splicing events contain sequences at each end which are also complementary to U1 RNA. Our data indicate that in the intron which we have examined the sequences at the 3' end of the intron are removed before those at the 5' end.

Animals↗

PubMed1980

The collagen gene: evidence for its evolutinary assembly by amplification of a DNA segment containing an exon of 54 bp.

We have determined the size and sequence of 8 exons in the gene that specifies chick type 1 alpha 2 collagen. These 8 exons represent three different segments of the gene, but all encode information for the helical portion of the protein. Seven exons have a length of 54 bp, and the 8th has a size of 99 bp. The sequences within these exons vary except for th glycine codons, which occur every third triplet. Each exon begins with a glycine codon and ends with a triplet that precedes a glycine codon. The size and the sequences of the introns do not show any homology except at their ends. Of 7 introns examined the first six bases at the 5' end of 5 of these are identical. The sequences at the 3' end of the introns also show homologies. Our results imply that the ancestral gene for collagen arose by multiple duplications of a single genetic unit containing a 54 bp condig segment. The sequences within these exons drifted by successive point mutations and in some cases by additions or deletions of 9 bp or multiples of 9 bp.

Animals↗

PubMed1980

Isolation and characterization of overlapping genomic clones covering the chicken alpha 2 (type I) collagen gene.

A series of overlapping recombinant clones, which cover the alpha 2 (type I) collagen gene, have been isolated by stepwise screening of two libraries of chicken genomic DNA fragments. The first genomic clone was isolated by using a cloned cDNA containing alpha 2 collagen DNA sequences as hybridization probe. The other clones were obtained by a sequence of screenings using defined fragments of the successive genomic clones as hybridization probes. Several types of experiments indicated that the DNA of these clones are truly overlapping and span 55 kilobase pairs of contiguous DNA sequences in the chicken genome. Sequence analysis of small DNA segments of some of these clones confirm that they contain coding sequences which specify alpha 2 collagen. Electron microscopic analysis of hybrids between type I alpha 2 collagen mRNA and the overlapping genomic clones indicates that the chicken alpha 2 collagen gene has a length of at least 37 kilobases, about 7.4 times longer than the corresponding translatable cytoplasmic mRNA. The coding information for alpha 2 collagen is distributed in more than 50 coding sequences which are interrupted by intervening sequences of various sizes. The structure of the gene implies that the conversion of precursor RNA to mature mRNA for alpha 2 collagen includes at least 50 splicing events.

Animals↗

PubMed1976

The nucleotide sequence of asparagine tRNA from Escherichia coli.

The nucleotide seuquence of Escherichia coli asparagine tRNA was determined to be pU-C-C-U-C-U-G-s4U-A-G-U-U-C-A-G-D-C-G-G-D-A-G-A-A-C-G-G-C-G-G-A-C-U-Q-U-U-t6A-A-phi-C-C-G-U-A-U-m G-U-C-A-C-U-G-G-T-phi-C-G-A-G-U-C-C-A-G-U-C-A-G-A-G-G-A-G-C-C-AOH. Its D-stem and D-loop have almost the same sequence as Escherichia coli aspartate tRNA.

Asparagine↗