TY - JOUR
T1 - Restoration of mRNA splicing by a second-site intragenic suppressor in the T4 ribonucleotide reductase (small subunit) self-splicing intron
AU - Khan, Asad U.
AU - Ahmad, Masood
AU - Lal, Sunil K.
N1 - Funding Information:
We thank Drs. D. H. Hall, D. Shub, and J. Gott for their technical assistance. We are also grateful to Drs. V. S. Chauhan and S. Jameel for their help with this project. This research was supported by the University Grants Commission, fellowship to A.U.K., and internal funds from ICGEB.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2000/2/16
Y1 - 2000/2/16
N2 - The nrdB gene of bacteriophage T4 codes for the small subunit of ribonucleotide reductase and contains a 598-base self-splicing intron which is closely related to other group I introns of T4 and eukaryotes. Thirty-one mutants causing splicing defects in the nrdB intron were isolated. Twenty-three EMS-induced revertants for these 31 primary mutants were isolated by the strategic usage of the white halo plaque phenotype. We mapped these revertants by marker rescue using subclones of the nrdB gene. Some of these second-site mutations mapped to regions currently predicted by the secondary structure model of the nrdB intron. One of these suppressor mutants (nrdB753R) was found to be intragenic by marker rescue with the whole nrdB gene. However, this mutation failed to map within the nrdB intron. Splicing assays showed that this pseudorevertant restored splicing proficiency of the nrdB primary mutation to almost wild-type conditions. This is the first example of a mutation within the exons of a gene containing a self-splicing intron that is capable of restoring a self-splicing defect caused by a primary mutation within the intron. In addition, two other suppressor mutations are of interest (nrdB429R and nrdB399R). These suppressors were able to restore their primary 5' defect but in turn create a 3' splicing defect. Both of these revertants mapped in different regions of the intron with respect to their primary mutations. (C) 2000 Academic Press.
AB - The nrdB gene of bacteriophage T4 codes for the small subunit of ribonucleotide reductase and contains a 598-base self-splicing intron which is closely related to other group I introns of T4 and eukaryotes. Thirty-one mutants causing splicing defects in the nrdB intron were isolated. Twenty-three EMS-induced revertants for these 31 primary mutants were isolated by the strategic usage of the white halo plaque phenotype. We mapped these revertants by marker rescue using subclones of the nrdB gene. Some of these second-site mutations mapped to regions currently predicted by the secondary structure model of the nrdB intron. One of these suppressor mutants (nrdB753R) was found to be intragenic by marker rescue with the whole nrdB gene. However, this mutation failed to map within the nrdB intron. Splicing assays showed that this pseudorevertant restored splicing proficiency of the nrdB primary mutation to almost wild-type conditions. This is the first example of a mutation within the exons of a gene containing a self-splicing intron that is capable of restoring a self-splicing defect caused by a primary mutation within the intron. In addition, two other suppressor mutations are of interest (nrdB429R and nrdB399R). These suppressors were able to restore their primary 5' defect but in turn create a 3' splicing defect. Both of these revertants mapped in different regions of the intron with respect to their primary mutations. (C) 2000 Academic Press.
UR - http://www.scopus.com/inward/record.url?scp=0034673317&partnerID=8YFLogxK
U2 - 10.1006/bbrc.2000.2144
DO - 10.1006/bbrc.2000.2144
M3 - Article
C2 - 10679208
AN - SCOPUS:0034673317
VL - 268
SP - 359
EP - 364
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 2
ER -