A promoter reported in cDNA corresponding to IRES sequence: yes
The total number of notable open-reading frames (ORFs): 2
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: homogeneous_population_of_molecules_confirmed
Integrity (uniformity) of mRNA tested using RNase protection: homogeneous_population_of_molecules_confirmed
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: no_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
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: 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 description of the protein encoded in this ORF: c-myc proto-oncogene, isoform c-myc2(AUG translation initiation codon), 64 kDa.
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: no
The ORF absolute position (the base range includes START and STOP codons or their equivalents): 396-1955
Remarks:
This is the sequence encoding mRNA transcribed from major P2 promotor. P2 mRNA encodes two proteins of 67 and
64 kDa in size designated c-myc1 and c-myc2 respectively:
- c-myc1 is produced when alternative initiation of translation starting at non-canonical CUG codon occurs
- c-myc2 is translated from conventional AUG codon protein represents prevalent isoform of c-myc in mammalian
cells
Nanbru et al., 1997 have used bi- and tri-cistronic constructs to study c-myc IRES. The two internal TATA
boxes present in c-myc UTR were masked by directed mutagenesis. Integrity of the transcripts was tested by
Northern blot. Also T7 in vitro transcripts and rabbit reticulocyte lysates were used to demonstrate IRES
activity. They conclude IRES position between -363 and -94b upstream the CUG initiation codon.
Integrity of the transcripts from pGL3Rutr transfected HeLa cells was tested by RNase protection assay. The
protected fragment contained 64b from 3'-end of Rluc, 447b of the intercistronic region and 101b from the
5'-end of Fluc. No direct RNA transfection performed or in vitro translation or promoter-less plasmid used to
test cryptic promoter presence (Stoneley et al., 1998).
Johannes et al., 1998 have shown that c-myc is associated with polysomes during poliovirus infection and that
the protein is actually being synthesized.
Stoneley et al., 2000 reported that in vaccinia virus infected human TK143 cells expressing T7 polymerase the
c-myc IRES is not functional due to the lack of "nuclear experience". Further, c-myc IRES in capped GpppG
bicistronic run-off transcripts with poly(A) of length 30 was not functional either. They have also shown in
Figure 2 that the IRES is most active in HeLa cells, with decreasing activity in MRC5, HepG2, GM637, HK293,
COS7, MCF7, Balb/c 3T3, MEL cell lines. Finally, it was concluded that c-myc IRES requires a non-canonical
translation initiation cofactor like entero- and rhinovirus IRESs and unlike cardio- and aphtovirus IRESs
(as originally reported by Borman et al. (1997), Nucleic Acids Res. 25:925-932).
Subkhankulova et al., 2001 studied effect of various stresses on c-myc and Apaf-1 IRES activity.
Creancier et al., 2001 have shown the activity of pRF based plasmids containing c-myc IRES in many cell lines
and embryonic/adult mouse tissues (c-myc IRES found inactive in adult tissues).
Kim et al., 2003 have shown that hnRNP C1 stimulates the IRES activity through its binding to internal polyU
sequence. hnRNP C1 also stimulates in a dose dependent manner translation from a downstream cistron (FFluc) in
rabbit reticulocyte lysate.
Shi et al., 2005 tested c-myc in pRF promoter-less plasmids (SV40 promoter deleted) and integrity of the
transcripts by Northern blot. T7 transcripts poorly translated in rabbit reticulocyte lysates.
Bert et al. (2006) tested c-myc IRES in HeLa cells using promoter-less plasmids with or without the enhancer
left in (Figure 2). They showed there is a cryptic promoter activatable when the enhancer is left in.
The IRES absolute position (the range includes START and STOP codons or their equivalents): 1-393
Conclusion: probably_not_IRES
How IRES boundaries were determined: experimentally_determined
The sequence of IRES region aligned to its secondary structure (if available):
There is no Vienna RNA package installed on the server or some error/warning messages were output. Due to that maybe we cannot prepare 2D structures for display. The error/warning message was:
WARNING: bases 15 and 208 (GG) can't pair!
WARNING: bases 17 and 206 (AG) can't pair!
WARNING: bases 19 and 204 (AG) can't pair!
WARNING: bases 20 and 203 (GG) can't pair!
WARNING: bases 21 and 202 (GG) can't pair!
WARNING: bases 24 and 200 (GG) can't pair!
WARNING: bases 26 and 199 (GA) can't pair!
WARNING: bases 29 and 173 (CC) can't pair!
WARNING: bases 31 and 171 (GG) can't pair!
WARNING: bases 33 and 170 (CU) can't pair!
WARNING: bases 36 and 168 (CC) can't pair!
WARNING: bases 40 and 165 (CA) can't pair!
WARNING: bases 44 and 162 (GG) can't pair!
WARNING: bases 48 and 158 (GG) can't pair!
WARNING: bases 49 and 156 (AC) can't pair!
WARNING: bases 56 and 155 (GG) can't pair!
WARNING: bases 120 and 128 (CC) can't pair!
WARNING: bases 121 and 127 (CC) can't pair!
WARNING: bases 136 and 150 (CA) can't pair!
WARNING: bases 137 and 149 (CC) can't pair!
WARNING: bases 138 and 148 (CC) can't pair!
WARNING: bases 140 and 146 (CC) can't pair!
WARNING: bases 141 and 145 (UC) can't pair!
Rendering structure of c-myc mRNA 393 nt long with energy of 99997.00 kcal/mol as calculated by RNAeval using VARNA Java applet with some IRESite improvements (see VARNA modified by IRESite). Hold left mouse button to move structure parts, hold right mouse button to move whole structure, use mouse wheel to zoom. Right mouse-click opens a menu to export into JPG/SVG and many other options.
Remarks:
1-393 base range has comparable IRES activity to 1-340 region. Further deletions of 1-340 region result in
lower IRES activity. Please note that the very last 2 bases of 5'-UTR were not cloned into the pGL3Rutr alias
pRMF vector to keep the putative IRES 'in frame' with the initiator ATG codon (Evans et al. (2003), Fig. 1B
legend) while they have been replaced by 'cc' of NcoI site 'ccATGg'.
Bert et al. (2006) reported c-myc IRES is only 3x more functional than a negative control while EMCV IRES was
221x in direct RNA transfection (Figure 4).
Andreev et al. (2009) objected existence of the c-myc IRES.
The absolute position of the experimentally mapped region (the range includes START and STOP codons or their equivalents): 1-398
The underlying nucleic acid sequence and structure of the mapped region:
There is no Vienna RNA package installed on the server or some error/warning messages were output. Due to that maybe we cannot prepare 2D structures for display. The error/warning message was:
WARNING: bases 15 and 208 (GG) can't pair!
WARNING: bases 17 and 206 (AG) can't pair!
WARNING: bases 19 and 204 (AG) can't pair!
WARNING: bases 20 and 203 (GG) can't pair!
WARNING: bases 21 and 202 (GG) can't pair!
WARNING: bases 24 and 200 (GG) can't pair!
WARNING: bases 26 and 199 (GA) can't pair!
WARNING: bases 29 and 173 (CC) can't pair!
WARNING: bases 31 and 171 (GG) can't pair!
WARNING: bases 33 and 170 (CU) can't pair!
WARNING: bases 36 and 168 (CC) can't pair!
WARNING: bases 40 and 165 (CA) can't pair!
WARNING: bases 44 and 162 (GG) can't pair!
WARNING: bases 48 and 158 (GG) can't pair!
WARNING: bases 49 and 156 (AC) can't pair!
WARNING: bases 56 and 155 (GG) can't pair!
WARNING: bases 120 and 128 (CC) can't pair!
WARNING: bases 121 and 127 (CC) can't pair!
WARNING: bases 136 and 150 (CA) can't pair!
WARNING: bases 137 and 149 (CC) can't pair!
WARNING: bases 138 and 148 (CC) can't pair!
WARNING: bases 140 and 146 (CC) can't pair!
WARNING: bases 141 and 145 (UC) can't pair!
Rendering structure of c-myc mRNA 398 nt long with energy of 99997.00 kcal/mol as calculated by RNAeval using VARNA Java applet with some IRESite improvements (see VARNA modified by IRESite). Hold left mouse button to move structure parts, hold right mouse button to move whole structure, use mouse wheel to zoom. Right mouse-click opens a menu to export into JPG/SVG and many other options.
Remarks:
Probing agents: DMS, kethoxal and CMCT
4.1.1. Chemicals used to characterize at least partially the 2D structure.
Chemical reagent used with its respective buffer:
ss_experiment_with_chemical_id: 5
The temperature (in degrees of Celsia): 0
The chemical reagent used to determine the 2D structure: CMCT
Chemical reagent used with its respective buffer:
Version: 0
pH 8.00
Li+ [mM] 0
Na+ [mM] 0
K+ [mM] 150.00
Mg2+ [mM] 10.00
Ca2+ [mM] 0
Cl- [mM] 100.00
Tris [mM] 0
BSA [mM] 0
HEPES [mM] 0
EGTA [mM] 0
EDTA [mM] 0.50
cacodylate [mM] 0
Chemical reagent used with its respective buffer:
ss_experiment_with_chemical_id: 6
The temperature (in degrees of Celsia): 0
The chemical reagent used to determine the 2D structure: DMS
Chemical reagent used with its respective buffer:
Version: 0
pH 7.00
Li+ [mM] 0
Na+ [mM] 0
K+ [mM] 100.00
Mg2+ [mM] 10.00
Ca2+ [mM] 0
Cl- [mM] 100.00
Tris [mM] 10.00
BSA [mM] 0
HEPES [mM] 0
EGTA [mM] 0
EDTA [mM] 0.50
cacodylate [mM] 0
Chemical reagent used with its respective buffer:
ss_experiment_with_chemical_id: 7
The temperature (in degrees of Celsia): 0
The chemical reagent used to determine the 2D structure: kethoxal