Abstract
Over forty aspartate transcarbamylase mutants (pyr B) of Salmonella typhimurium have been surveyed. The mutants have been classified as to mutational type and used to construct a genetic map of the pyr B locus. The direction of transcription across this locus is inferred from the fact that several amber nonsense mutations at one extreme end of the map leave the cell with residual pyr B function. Seven nonsense and frameshift mutants of the pyr B gene were selected and assayed for their content of regulatory subunit; all possessed reduced but detectable levels of the subunit. Since pyr B mutants lack catalytic activity but possess detectable regulatory subunit we conclude that the pyr B locus codes only for the catalytic subunit. Two deletion mutants were isolated that lack the entire pyr B locus and produce no detectable regulatory subunit; we infer that the structural gene for regulatory subunit is adjacent to the pyr B locus. The reduced level of regulatory subunit in pyr B mutants is consistent with a polarity effect of pyr B mutations on an adjacent gene for this subunit. No point mutations of the regulatory subunit structural gene have been found.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 363-378 |
| Number of pages | 16 |
| Journal | Journal of Molecular Biology |
| Volume | 76 |
| Issue number | 3 |
| DOIs | |
| State | Published - May 25 1973 |
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ASJC Scopus subject areas
- Virology
Cite this
Structural genes for catalytic and regulatory subunits of aspartate transcarbamylase. / Syvanen, J. Michael; Roth, John R.
In: Journal of Molecular Biology, Vol. 76, No. 3, 25.05.1973, p. 363-378.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Structural genes for catalytic and regulatory subunits of aspartate transcarbamylase
AU - Syvanen, J. Michael
AU - Roth, John R.
PY - 1973/5/25
Y1 - 1973/5/25
N2 - Over forty aspartate transcarbamylase mutants (pyr B) of Salmonella typhimurium have been surveyed. The mutants have been classified as to mutational type and used to construct a genetic map of the pyr B locus. The direction of transcription across this locus is inferred from the fact that several amber nonsense mutations at one extreme end of the map leave the cell with residual pyr B function. Seven nonsense and frameshift mutants of the pyr B gene were selected and assayed for their content of regulatory subunit; all possessed reduced but detectable levels of the subunit. Since pyr B mutants lack catalytic activity but possess detectable regulatory subunit we conclude that the pyr B locus codes only for the catalytic subunit. Two deletion mutants were isolated that lack the entire pyr B locus and produce no detectable regulatory subunit; we infer that the structural gene for regulatory subunit is adjacent to the pyr B locus. The reduced level of regulatory subunit in pyr B mutants is consistent with a polarity effect of pyr B mutations on an adjacent gene for this subunit. No point mutations of the regulatory subunit structural gene have been found.
AB - Over forty aspartate transcarbamylase mutants (pyr B) of Salmonella typhimurium have been surveyed. The mutants have been classified as to mutational type and used to construct a genetic map of the pyr B locus. The direction of transcription across this locus is inferred from the fact that several amber nonsense mutations at one extreme end of the map leave the cell with residual pyr B function. Seven nonsense and frameshift mutants of the pyr B gene were selected and assayed for their content of regulatory subunit; all possessed reduced but detectable levels of the subunit. Since pyr B mutants lack catalytic activity but possess detectable regulatory subunit we conclude that the pyr B locus codes only for the catalytic subunit. Two deletion mutants were isolated that lack the entire pyr B locus and produce no detectable regulatory subunit; we infer that the structural gene for regulatory subunit is adjacent to the pyr B locus. The reduced level of regulatory subunit in pyr B mutants is consistent with a polarity effect of pyr B mutations on an adjacent gene for this subunit. No point mutations of the regulatory subunit structural gene have been found.
UR - http://www.scopus.com/inward/record.url?scp=0015788662&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0015788662&partnerID=8YFLogxK
U2 - 10.1016/0022-2836(73)90510-X
DO - 10.1016/0022-2836(73)90510-X
M3 - Article
C2 - 4581524
AN - SCOPUS:0015788662
VL - 76
SP - 363
EP - 378
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
SN - 0022-2836
IS - 3
ER -