Gokul Das - Academia.edu (original) (raw)
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Papers by Gokul Das
Molecular and Cellular Biology, 1985
The presence of a surrogate TATA box sequence located ca. 30 nucleotides upstream of the major la... more The presence of a surrogate TATA box sequence located ca. 30 nucleotides upstream of the major late RNA start site at nucleotide position (np) 325 (Brady et al., Cell 31:625-633, 1982) has been confirmed, and its structural specificity has been determined by the generation of additional base substitution mutations at the KpnI restriction site (np 294) in cloned simian virus 40 DNA. Two mutants generated new RNA initiation sites upstream of the np 325 start site and continued to utilize the authentic start site, but with decreased efficiency. The replacement of either one or both cytosines by thymines at np 298 and np 299 specifically enhanced in vitro transcription from the np 325 start site by 430 and 800%, respectively. This enhancement was due to conversion of the simian virus 40 late promoter present in the wild-type virus to a sequence that is similar to the TATA box present in the simian virus 40 early promoter.
Cell, 1982
Transcriptional analysis of SV40 late promoter mutants indicates that the DNA sequence 5'-GGTACCT... more Transcriptional analysis of SV40 late promoter mutants indicates that the DNA sequence 5'-GGTACCTAACCS' (map positions 294-304) is important in the control of SV40 late RNA expression. C to T base substitutions at map positions 298,299 and 304 increased initiation of late RNA synthesis at map position 325 five to ten fold. G to A base substitutions at map positions 294 and 295 decreased RNA initiation by a factor of 2 to 3. Deletion of nucleotides 295-298 reduced RNA initiation by a factor of 4 to 5. Sl analysis of in vivo RNA, isolated 24-38 hr after infection, demonstrated that the four base deletion not only decreased RNA initiation at nucleotide 325, but also increased RNA initiation at three alternate sites located approximately 125 nucleotides upstream from the major late RNA initiation site.
Molecular and Cellular Biology, 1985
The presence of a surrogate TATA box sequence located ca. 30 nucleotides upstream of the major la... more The presence of a surrogate TATA box sequence located ca. 30 nucleotides upstream of the major late RNA start site at nucleotide position (np) 325 (Brady et al., Cell 31:625-633, 1982) has been confirmed, and its structural specificity has been determined by the generation of additional base substitution mutations at the KpnI restriction site (np 294) in cloned simian virus 40 DNA. Two mutants generated new RNA initiation sites upstream of the np 325 start site and continued to utilize the authentic start site, but with decreased efficiency. The replacement of either one or both cytosines by thymines at np 298 and np 299 specifically enhanced in vitro transcription from the np 325 start site by 430 and 800%, respectively. This enhancement was due to conversion of the simian virus 40 late promoter present in the wild-type virus to a sequence that is similar to the TATA box present in the simian virus 40 early promoter.
Cell, 1982
Transcriptional analysis of SV40 late promoter mutants indicates that the DNA sequence 5'-GGTACCT... more Transcriptional analysis of SV40 late promoter mutants indicates that the DNA sequence 5'-GGTACCTAACCS' (map positions 294-304) is important in the control of SV40 late RNA expression. C to T base substitutions at map positions 298,299 and 304 increased initiation of late RNA synthesis at map position 325 five to ten fold. G to A base substitutions at map positions 294 and 295 decreased RNA initiation by a factor of 2 to 3. Deletion of nucleotides 295-298 reduced RNA initiation by a factor of 4 to 5. Sl analysis of in vivo RNA, isolated 24-38 hr after infection, demonstrated that the four base deletion not only decreased RNA initiation at nucleotide 325, but also increased RNA initiation at three alternate sites located approximately 125 nucleotides upstream from the major late RNA initiation site.