The nucleic acid data:
IRESite Id: 132 Version: 7
Originaly submitted by: Martin Mokrejš
Reviewed by: Martin Mokrejš Last change: 2007-05-15 00:00:00
IRESite record type:
  plasmid_with_promoter_and_putative_IRES_translationally_characterized
The shape of the nucleic acid molecule translated:
  linear
The quality of the mRNA/+RNA sequence:
  our_best_guess
The mRNA/+RNA description: 
Bicistronic mRNA containing renilla and firefly luciferases with BCL2 IRES segment in the intercistronic
region. The mRNA is spliced and does not contain the chimeric intron. The sequence ends at its 3'-end right
after the poly(A) signal from bovine growth hormone (BGH) mRNA and thus the 3'-UTR might be slightly wrong (it
is unknown what region of the BGH signal was transcribed and where the poly(A) tail was added).
The mRNA/+RNA sequence represented in the +DNA notation:


Warning: mRNA sequence when devoid of trailing 'A's is still not a substring of the plasmid sequence. Is it because an intron is spliced out? Stay calm then. :-)
Credibility of mRNA sequence:
  reverse_engineered_sequence_and_should_match_experiment_except_3UTR
The name of the plasmid:
pRL-BCL2-FL
The name of the promoter used to express this mRNA:
  CMV
The in vivo produced transcripts are heterogeneous (due to any of promoter?/splicing?/cleavage?/breakage?):
  yes
The in vivo produced heterogeneous transcripts occur due to alternative splicing:
  yes
A promoter reported in cDNA corresponding to IRES sequence:
  yes
Summary of possible issues when IRES cDNA is experimentally transcribed in vivo:
Summary of experiments studying integrity of the in vivo transcripts in a particular host:
Integrity (uniformity) of mRNA tested using Northern-blot:
not_tested
Integrity (uniformity) of mRNA tested using RNase protection:
not_tested
Integrity (uniformity) of mRNA tested using 5'-RACE:
not_tested
Integrity (uniformity) of mRNA tested using primer extension :
not_tested
Integrity (uniformity) of mRNA tested using RT-PCR:
not_tested
Integrity (uniformity) of mRNA tested using real-time quantitative polymerase chain reaction (rtqPCR):
not_tested
Integrity (uniformity) of mRNA tested using RNAi:
not_tested
Integrity (uniformity) of mRNA tested using S1 nuclease mapping:
not_tested
Cryptic promoter presence was confirmed by expression from a promoter-less plasmid:
weak_promoter_confirmed
Cryptic promoter presence was confirmed in an experimental setup involving inducible promoter:
not_tested
Integrity (uniformity) of mRNA molecules or possible promoter presence expressed in vivo was tested using another method, please specify in Remarks:
not_tested
The organism used:
Homo sapiens HEK 293T/17 (ATCC CRL-11268)
The abbreviated name of the donor gene or virus from which this IRES was excised and inserted into the plasmid:
BCL2
The origin of IRES in the plasmid:
  nuclear
The donor organism of the IRES segment:
Homo sapiens HeLa (ATCC CCL-2)
The DNA sequence of the plasmid in (+) orientation annotated by its secondary structure:


GenBank formatted file with annotated plasmid sequence hyperlinked from vector image map:
pRL-BCL2-FL.jpg
The total number of notable open-reading frames (ORFs):
  2
Notable Open-Reading Frames (ORFs; protein coding regions) in the mRNA/+RNA sequence:
ORF
ORF position:   1
Version: 0
Originaly submitted by: Martin Mokrejš Reviewed by: Martin Mokrejš
The abbreviated name of this ORF/gene:
RLuc
The description of the protein encoded in this ORF:
Renilla luciferase
The translational frameshift (ribosome slippage) involved:
  0
The ribosome read-through involved:
  no
The alternative forms of this protein occur by the alternative initiation of translation:
  not tested
The ORF absolute position (the base range includes START and STOP codons or their equivalents):
  190-1125
ORF
ORF position:   2
Version: 1 Last change: 2006-10-30 00:00:00
Originaly submitted by: Martin Mokrejš Reviewed by: Martin Mokrejš
The abbreviated name of this ORF/gene:
FLuc-fusion
The description of the protein encoded in this ORF:
Firefly luciferase fused N-terminally with 6 extra aminoacid residues (including the initiator ATG) from BCL2 protein.
The translational frameshift (ribosome slippage) involved:
  0
The ribosome read-through involved:
  no
The alternative forms of this protein occur by the alternative initiation of translation:
  not tested
The ORF absolute position (the base range includes START and STOP codons or their equivalents):
  2279-3949
Remarks:
Negligible promoter activity attributable to BCL2 IRES was shown in Fig. 3A using promoter-less plasmid.
Alternatively spliced transcripts from this plasmid were confirmed in Fig. 3C.
Citations:
Sherrill K. W., Byrd M. P., Van Eden M. E., Lloyd R. E. (2004) BCL-2 translation is mediated via internal ribosome entry during cell stress. J. Biol. Chem. 279(28):29066-29074
IRESs:
IRES:
Version: 4 Last change: 2007-01-23 00:00:00
Originaly submitted by: Martin Mokrejš Reviewed by: Martin Mokrejš
The IRES name:
  BCL2
The functional status of IRES:
  functional
The IRES absolute position (the range includes START and STOP codons or their equivalents):
  1141-2278
How IRES boundaries were determined:
experimentally_determined
5'-end of IRES relative to last base of the STOP codon of the upstream ORF:
  16
3'-end of IRES relative to last base of the STOP codon of the upstream ORF:
  1153
5'-end of IRES relative to first base of the START codon of the downstream ORF:
  -1138
3'-end of IRES relative to first base of the START codon of the downstream ORF:
  -1
The sequence of IRES region aligned to its secondary structure (if available):


The translation experiments:
Translation results:
IRESite Translation Id: 96
Version: 4 Last change: 2006-10-30 00:00:00
Originaly submitted by: Martin Mokrejš Reviewed by: Martin Mokrejš
The translation method used to study IRES function:
in vivo
The organism used for translation:
Homo sapiens HEK 293T/17 (ATCC CRL-11268)
The temperature (in degrees of Celsia):
37
The relative translation efficiency in % of this IRES:
  140.000
Name of IRES used as the positive control:
  HCV_type_1b
Name of the plasmid used as the positive control.
pRL-HCV-FL
Name of the plasmid used as the negative control.
pRL-FL
IRESite Id of the plasmid used as positive control.
  131
IRESite Id of the plasmid used as negative control.
  119
The relative translation efficiency in % of the positive control:
  100.000
The relative translation efficiency in % of the negative control:
  2.000
The size (length) of intercistronic region in the positive control:
485
The size (length) of intercistronic region in the negative control:
28
The effect of 5'-cap analogs on translation:
not tested
Rapamycin affects translation:
not tested
Type of RNA subject to translation:
  endogenous_nuclear_RNA_Pol_II_transcript
Remarks:
The results from Fig. 3A do not form the supporting evidence for existence of IRES in BCL2 (the direct mRNA
transfection is the key experiment, see IRESite Id: 114 namely its subsection IRESite Translation Id: 97).
They only demonstrate how the luciferase values obtained are biased by presence of the cryptic promoter in HCV
IRES and by the promoter in BCL2 and by aberrant splicing from pRL-BCL2-FL plasmid (where splice acceptor site
was uncovered in BCL2 IRES and which causes alternatively splices with the chimeric intron contained in the
plasmid). Those alternative transcripts are functionally monocistronic (Fig. 3B, C).
Citations:
Sherrill K. W., Byrd M. P., Van Eden M. E., Lloyd R. E. (2004) BCL-2 translation is mediated via internal ribosome entry during cell stress. J. Biol. Chem. 279(28):29066-29074
Last change to the database: 2015-04-16 16:45:23 GMT+1