Human Gene POLR1A (ENST00000263857.11_12) from GENCODE V47lift37
  Description: RNA polymerase I subunit A (from RefSeq NM_015425.6)
Gencode Transcript: ENST00000263857.11_12
Gencode Gene: ENSG00000068654.17_14
Transcript (Including UTRs)
   Position: hg19 chr2:86,247,339-86,333,009 Size: 85,671 Total Exon Count: 34 Strand: -
Coding Region
   Position: hg19 chr2:86,254,546-86,332,899 Size: 78,354 Coding Exon Count: 34 

Page IndexSequence and LinksUniProtKB CommentsPrimersMalaCardsCTD
Gene AllelesRNA-Seq ExpressionMicroarray ExpressionRNA StructureProtein StructureOther Species
GO AnnotationsmRNA DescriptionsPathwaysOther NamesModel InformationMethods
Data last updated at UCSC: 2024-08-22 23:36:26

-  Sequence and Links to Tools and Databases
 
Genomic Sequence (chr2:86,247,339-86,333,009)mRNA (may differ from genome)Protein (1720 aa)
Gene SorterGenome BrowserOther Species FASTAVisiGeneGene interactionsTable Schema
AlphaFoldBioGPSEnsemblEntrez GeneExonPrimerGeneCards
HGNCMalacardsMGIOMIMPubMedReactome
UniProtKBWikipediaBioGrid CRISPR DB

-  Comments and Description Text from UniProtKB
  ID: RPA1_HUMAN
DESCRIPTION: RecName: Full=DNA-directed RNA polymerase I subunit RPA1; Short=RNA polymerase I subunit A1; EC=2.7.7.6; AltName: Full=A190; AltName: Full=DNA-directed RNA polymerase I largest subunit; AltName: Full=DNA-directed RNA polymerase I subunit A; AltName: Full=RNA polymerase I 194 kDa subunit; Short=RPA194;
FUNCTION: DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Largest and catalytic core component of RNA polymerase I which synthesizes ribosomal RNA precursors. Forms the polymerase active center together with the second largest subunit. A single stranded DNA template strand of the promoter is positioned within the central active site cleft of Pol I. A bridging helix emanates from RPA1 and crosses the cleft near the catalytic site and is thought to promote translocation of Pol I by acting as a ratchet that moves the RNA-DNA hybrid through the active site by switching from straight to bent conformations at each step of nucleotide addition (By similarity).
CATALYTIC ACTIVITY: Nucleoside triphosphate + RNA(n) = diphosphate + RNA(n+1).
SUBUNIT: Component of the RNA polymerase I (Pol I) complex consisting of at least 13 subunits. Interacts with MYO1C. Interacts with ERBB2 (By similarity).
INTERACTION: P04626:ERBB2; NbExp=16; IntAct=EBI-359472, EBI-641062;
SUBCELLULAR LOCATION: Nucleus, nucleolus (By similarity).
SIMILARITY: Belongs to the RNA polymerase beta' chain family.
SEQUENCE CAUTION: Sequence=AAC99959.1; Type=Frameshift; Positions=1114, 1469; Sequence=AAD09356.1; Type=Frameshift; Positions=1114;

-  Primer design for this transcript
 

Primer3Plus can design qPCR Primers that straddle exon-exon-junctions, which amplify only cDNA, not genomic DNA.
Click here to load the transcript sequence and exon structure into Primer3Plus

Exonprimer can design one pair of Sanger sequencing primers around every exon, located in non-genic sequence.
Click here to open Exonprimer with this transcript

To design primers for a non-coding sequence, zoom to a region of interest and select from the drop-down menu: View > In External Tools > Primer3


-  MalaCards Disease Associations
  MalaCards Gene Search: POLR1A
Diseases sorted by gene-association score: acrofacial dysostosis, cincinnati type* (1241), acrofacial dysostosis (40), dysostosis (18), warsaw breakage syndrome (17), kidney hypertrophy (9), swine influenza (6), treacher collins syndrome 1 (5)
* = Manually curated disease association

-  Comparative Toxicogenomics Database (CTD)
  The following chemicals interact with this gene

+  Common Gene Haplotype Alleles
  Press "+" in the title bar above to open this section.

-  RNA-Seq Expression Data from GTEx (53 Tissues, 570 Donors)
  Highest median expression: 6.95 RPKM in Cells - EBV-transformed lymphocytes
Total median expression: 172.41 RPKM



View in GTEx track of Genome Browser    View at GTEx portal     View GTEx Body Map

+  Microarray Expression Data
  Press "+" in the title bar above to open this section.

-  mRNA Secondary Structure of 3' and 5' UTRs
 
RegionFold EnergyBasesEnergy/Base
Display As
5' UTR -31.70110-0.288 Picture PostScript Text
3' UTR -2885.307207-0.400 Picture PostScript Text

The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.

-  Protein Domain and Structure Information
  InterPro Domains: Graphical view of domain structure
IPR015699 - DNA-dir_RNA_pol1_lsu
IPR000722 - RNA_pol_asu
IPR006592 - RNA_pol_N
IPR007080 - RNA_pol_Rpb1_1
IPR007066 - RNA_pol_Rpb1_3
IPR007083 - RNA_pol_Rpb1_4
IPR007081 - RNA_pol_Rpb1_5

Pfam Domains:
PF00623 - RNA polymerase Rpb1, domain 2
PF04983 - RNA polymerase Rpb1, domain 3
PF04997 - RNA polymerase Rpb1, domain 1
PF04998 - RNA polymerase Rpb1, domain 5
PF05000 - RNA polymerase Rpb1, domain 4

SCOP Domains:
48452 - TPR-like
64484 - beta and beta-prime subunits of DNA dependent RNA-polymerase

ModBase Predicted Comparative 3D Structure on O95602
FrontTopSide
The pictures above may be empty if there is no ModBase structure for the protein. The ModBase structure frequently covers just a fragment of the protein. You may be asked to log onto ModBase the first time you click on the pictures. It is simplest after logging in to just click on the picture again to get to the specific info on that model.

-  Orthologous Genes in Other Species
  Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
MouseRatZebrafishD. melanogasterC. elegansS. cerevisiae
No orthologNo orthologNo orthologNo orthologNo orthologNo ortholog
Gene DetailsGene Details Gene Details  
Gene SorterGene Sorter Gene Sorter  
 RGDEnsembl   
      
      

-  Gene Ontology (GO) Annotations with Structured Vocabulary
  Molecular Function:
GO:0001054 RNA polymerase I activity
GO:0003677 DNA binding
GO:0003682 chromatin binding
GO:0003899 DNA-directed 5'-3' RNA polymerase activity
GO:0005515 protein binding
GO:0008270 zinc ion binding
GO:0016740 transferase activity
GO:0016779 nucleotidyltransferase activity
GO:0046872 metal ion binding

Biological Process:
GO:0006351 transcription, DNA-templated
GO:0006361 transcription initiation from RNA polymerase I promoter
GO:0006363 termination of RNA polymerase I transcription
GO:0045815 positive regulation of gene expression, epigenetic
GO:1904750 negative regulation of protein localization to nucleolus

Cellular Component:
GO:0005634 nucleus
GO:0005654 nucleoplasm
GO:0005730 nucleolus
GO:0005736 DNA-directed RNA polymerase I complex


-  Descriptions from all associated GenBank mRNAs
  BC073824 - Homo sapiens cDNA clone IMAGE:6084234, partial cds.
JD346590 - Sequence 327614 from Patent EP1572962.
JD312109 - Sequence 293133 from Patent EP1572962.
JD312110 - Sequence 293134 from Patent EP1572962.
JD028019 - Sequence 9043 from Patent EP1572962.
JD312106 - Sequence 293130 from Patent EP1572962.
JD312107 - Sequence 293131 from Patent EP1572962.
JD312108 - Sequence 293132 from Patent EP1572962.
JD266167 - Sequence 247191 from Patent EP1572962.
JD566852 - Sequence 547876 from Patent EP1572962.
LF207190 - JP 2014500723-A/14693: Polycomb-Associated Non-Coding RNAs.
AK001612 - Homo sapiens cDNA FLJ10750 fis, clone NT2RP3001929.
JD498578 - Sequence 479602 from Patent EP1572962.
JD393260 - Sequence 374284 from Patent EP1572962.
JD543764 - Sequence 524788 from Patent EP1572962.
JD253537 - Sequence 234561 from Patent EP1572962.
JD189971 - Sequence 170995 from Patent EP1572962.
LF363011 - JP 2014500723-A/170514: Polycomb-Associated Non-Coding RNAs.
JD566034 - Sequence 547058 from Patent EP1572962.
JD117781 - Sequence 98805 from Patent EP1572962.
JD052653 - Sequence 33677 from Patent EP1572962.
JD342589 - Sequence 323613 from Patent EP1572962.
JD512934 - Sequence 493958 from Patent EP1572962.
JD173954 - Sequence 154978 from Patent EP1572962.
JD539958 - Sequence 520982 from Patent EP1572962.
JD389553 - Sequence 370577 from Patent EP1572962.
JD468038 - Sequence 449062 from Patent EP1572962.
JD383163 - Sequence 364187 from Patent EP1572962.
JD383393 - Sequence 364417 from Patent EP1572962.
JD197611 - Sequence 178635 from Patent EP1572962.
JD323144 - Sequence 304168 from Patent EP1572962.
JD250825 - Sequence 231849 from Patent EP1572962.
JD296586 - Sequence 277610 from Patent EP1572962.
JD219905 - Sequence 200929 from Patent EP1572962.
JD117665 - Sequence 98689 from Patent EP1572962.
JD366793 - Sequence 347817 from Patent EP1572962.
JD371612 - Sequence 352636 from Patent EP1572962.
JD518217 - Sequence 499241 from Patent EP1572962.
JD149549 - Sequence 130573 from Patent EP1572962.
JD364605 - Sequence 345629 from Patent EP1572962.
JD451535 - Sequence 432559 from Patent EP1572962.
JD139796 - Sequence 120820 from Patent EP1572962.
JD522740 - Sequence 503764 from Patent EP1572962.
JD351562 - Sequence 332586 from Patent EP1572962.
JD281627 - Sequence 262651 from Patent EP1572962.
JD442999 - Sequence 424023 from Patent EP1572962.
JD532301 - Sequence 513325 from Patent EP1572962.
JD495917 - Sequence 476941 from Patent EP1572962.
JD178192 - Sequence 159216 from Patent EP1572962.
JD266385 - Sequence 247409 from Patent EP1572962.
JD180277 - Sequence 161301 from Patent EP1572962.
JD065946 - Sequence 46970 from Patent EP1572962.
JD324129 - Sequence 305153 from Patent EP1572962.
JD054801 - Sequence 35825 from Patent EP1572962.
JD080863 - Sequence 61887 from Patent EP1572962.
JD145928 - Sequence 126952 from Patent EP1572962.
JD323783 - Sequence 304807 from Patent EP1572962.
JD441841 - Sequence 422865 from Patent EP1572962.
JD552089 - Sequence 533113 from Patent EP1572962.
JD452783 - Sequence 433807 from Patent EP1572962.
JD106750 - Sequence 87774 from Patent EP1572962.
JD515077 - Sequence 496101 from Patent EP1572962.
JD331161 - Sequence 312185 from Patent EP1572962.
JD166295 - Sequence 147319 from Patent EP1572962.
JD051593 - Sequence 32617 from Patent EP1572962.
JD212792 - Sequence 193816 from Patent EP1572962.
JD247096 - Sequence 228120 from Patent EP1572962.
JD451202 - Sequence 432226 from Patent EP1572962.
JD376044 - Sequence 357068 from Patent EP1572962.
JD333596 - Sequence 314620 from Patent EP1572962.
JD176338 - Sequence 157362 from Patent EP1572962.
JD138382 - Sequence 119406 from Patent EP1572962.
JD458023 - Sequence 439047 from Patent EP1572962.
JD069180 - Sequence 50204 from Patent EP1572962.
JD344716 - Sequence 325740 from Patent EP1572962.
JD447126 - Sequence 428150 from Patent EP1572962.
JD395906 - Sequence 376930 from Patent EP1572962.
JD056412 - Sequence 37436 from Patent EP1572962.
JD306673 - Sequence 287697 from Patent EP1572962.
JD169965 - Sequence 150989 from Patent EP1572962.
JD529568 - Sequence 510592 from Patent EP1572962.
JD430393 - Sequence 411417 from Patent EP1572962.
JD395905 - Sequence 376929 from Patent EP1572962.
JD326842 - Sequence 307866 from Patent EP1572962.
JD395904 - Sequence 376928 from Patent EP1572962.
JD306672 - Sequence 287696 from Patent EP1572962.
JD221165 - Sequence 202189 from Patent EP1572962.
JD064589 - Sequence 45613 from Patent EP1572962.
JD196950 - Sequence 177974 from Patent EP1572962.
JD314633 - Sequence 295657 from Patent EP1572962.
JD349382 - Sequence 330406 from Patent EP1572962.
JD283586 - Sequence 264610 from Patent EP1572962.
JD266618 - Sequence 247642 from Patent EP1572962.
JD376192 - Sequence 357216 from Patent EP1572962.
JD104558 - Sequence 85582 from Patent EP1572962.
JD156112 - Sequence 137136 from Patent EP1572962.
JD299573 - Sequence 280597 from Patent EP1572962.
JD561211 - Sequence 542235 from Patent EP1572962.
DQ599644 - Homo sapiens piRNA piR-37710, complete sequence.
JD411152 - Sequence 392176 from Patent EP1572962.
JD426288 - Sequence 407312 from Patent EP1572962.
JD304133 - Sequence 285157 from Patent EP1572962.
LF363010 - JP 2014500723-A/170513: Polycomb-Associated Non-Coding RNAs.
LF384124 - JP 2014500723-A/191627: Polycomb-Associated Non-Coding RNAs.
AK294447 - Homo sapiens cDNA FLJ56651 complete cds, highly similar to DNA-directed RNA polymerase I largest subunit (EC 2.7.7.6).
AK025568 - Homo sapiens cDNA: FLJ21915 fis, clone HEP03920.
AL117467 - Homo sapiens mRNA; cDNA DKFZp586M0122 (from clone DKFZp586M0122); partial cds.
BC017115 - Homo sapiens polymerase (RNA) I polypeptide A, 194kDa, mRNA (cDNA clone IMAGE:3919743), partial cds.
JD027580 - Sequence 8604 from Patent EP1572962.
JD034195 - Sequence 15219 from Patent EP1572962.
AK304131 - Homo sapiens cDNA FLJ58792 complete cds, highly similar to DNA-directed RNA polymerase I largest subunit (EC 2.7.7.6).
U33460 - Human DNA-directed RNA polymerase I largest subunit mRNA, complete cds.
AK302458 - Homo sapiens cDNA FLJ61191 complete cds, highly similar to DNA-directed RNA polymerase I largest subunit (EC 2.7.7.6).
JD196992 - Sequence 178016 from Patent EP1572962.
BC117173 - Homo sapiens polymerase (RNA) I polypeptide A, 194kDa, mRNA (cDNA clone MGC:150782 IMAGE:40125724), complete cds.
BC126303 - Homo sapiens polymerase (RNA) I polypeptide A, 194kDa, mRNA (cDNA clone MGC:161581 IMAGE:8992019), complete cds.
BC143345 - Homo sapiens polymerase (RNA) I polypeptide A, 194kDa, mRNA (cDNA clone MGC:176867 IMAGE:9051850), complete cds.
LF363007 - JP 2014500723-A/170510: Polycomb-Associated Non-Coding RNAs.
LF363006 - JP 2014500723-A/170509: Polycomb-Associated Non-Coding RNAs.
LF363005 - JP 2014500723-A/170508: Polycomb-Associated Non-Coding RNAs.
AH007280 - Homo sapiens DNA-directed RNA polymerase I largest subunit, precursor RNA, partial cds.
LF363004 - JP 2014500723-A/170507: Polycomb-Associated Non-Coding RNAs.
LF363001 - JP 2014500723-A/170504: Polycomb-Associated Non-Coding RNAs.
LF363000 - JP 2014500723-A/170503: Polycomb-Associated Non-Coding RNAs.
LF362999 - JP 2014500723-A/170502: Polycomb-Associated Non-Coding RNAs.
LF362998 - JP 2014500723-A/170501: Polycomb-Associated Non-Coding RNAs.
BC073968 - Homo sapiens polymerase (RNA) I polypeptide A, 194kDa, mRNA (cDNA clone IMAGE:6137570).
LF362997 - JP 2014500723-A/170500: Polycomb-Associated Non-Coding RNAs.
AK307490 - Homo sapiens cDNA, FLJ97438.
LF362996 - JP 2014500723-A/170499: Polycomb-Associated Non-Coding RNAs.
LF362995 - JP 2014500723-A/170498: Polycomb-Associated Non-Coding RNAs.
LF362994 - JP 2014500723-A/170497: Polycomb-Associated Non-Coding RNAs.
LF362989 - JP 2014500723-A/170492: Polycomb-Associated Non-Coding RNAs.
LF362988 - JP 2014500723-A/170491: Polycomb-Associated Non-Coding RNAs.
LF362987 - JP 2014500723-A/170490: Polycomb-Associated Non-Coding RNAs.
LF362985 - JP 2014500723-A/170488: Polycomb-Associated Non-Coding RNAs.
LF362982 - JP 2014500723-A/170485: Polycomb-Associated Non-Coding RNAs.
LF362976 - JP 2014500723-A/170479: Polycomb-Associated Non-Coding RNAs.
LF362975 - JP 2014500723-A/170478: Polycomb-Associated Non-Coding RNAs.
LF362974 - JP 2014500723-A/170477: Polycomb-Associated Non-Coding RNAs.
LF362973 - JP 2014500723-A/170476: Polycomb-Associated Non-Coding RNAs.
LF362972 - JP 2014500723-A/170475: Polycomb-Associated Non-Coding RNAs.
LF362971 - JP 2014500723-A/170474: Polycomb-Associated Non-Coding RNAs.
LF362970 - JP 2014500723-A/170473: Polycomb-Associated Non-Coding RNAs.
LF362969 - JP 2014500723-A/170472: Polycomb-Associated Non-Coding RNAs.
LF362967 - JP 2014500723-A/170470: Polycomb-Associated Non-Coding RNAs.
LF362966 - JP 2014500723-A/170469: Polycomb-Associated Non-Coding RNAs.
MA598588 - JP 2018138019-A/170514: Polycomb-Associated Non-Coding RNAs.
MA598587 - JP 2018138019-A/170513: Polycomb-Associated Non-Coding RNAs.
MA619701 - JP 2018138019-A/191627: Polycomb-Associated Non-Coding RNAs.
MA598584 - JP 2018138019-A/170510: Polycomb-Associated Non-Coding RNAs.
MA598583 - JP 2018138019-A/170509: Polycomb-Associated Non-Coding RNAs.
MA598582 - JP 2018138019-A/170508: Polycomb-Associated Non-Coding RNAs.
MA598581 - JP 2018138019-A/170507: Polycomb-Associated Non-Coding RNAs.
MA598578 - JP 2018138019-A/170504: Polycomb-Associated Non-Coding RNAs.
MA598577 - JP 2018138019-A/170503: Polycomb-Associated Non-Coding RNAs.
MA598576 - JP 2018138019-A/170502: Polycomb-Associated Non-Coding RNAs.
MA598575 - JP 2018138019-A/170501: Polycomb-Associated Non-Coding RNAs.
MA598574 - JP 2018138019-A/170500: Polycomb-Associated Non-Coding RNAs.
MA598573 - JP 2018138019-A/170499: Polycomb-Associated Non-Coding RNAs.
MA598572 - JP 2018138019-A/170498: Polycomb-Associated Non-Coding RNAs.
MA598571 - JP 2018138019-A/170497: Polycomb-Associated Non-Coding RNAs.
MA598566 - JP 2018138019-A/170492: Polycomb-Associated Non-Coding RNAs.
MA598565 - JP 2018138019-A/170491: Polycomb-Associated Non-Coding RNAs.
MA598564 - JP 2018138019-A/170490: Polycomb-Associated Non-Coding RNAs.
MA598562 - JP 2018138019-A/170488: Polycomb-Associated Non-Coding RNAs.
MA598559 - JP 2018138019-A/170485: Polycomb-Associated Non-Coding RNAs.
MA598553 - JP 2018138019-A/170479: Polycomb-Associated Non-Coding RNAs.
MA598552 - JP 2018138019-A/170478: Polycomb-Associated Non-Coding RNAs.
MA598551 - JP 2018138019-A/170477: Polycomb-Associated Non-Coding RNAs.
MA598550 - JP 2018138019-A/170476: Polycomb-Associated Non-Coding RNAs.
MA598549 - JP 2018138019-A/170475: Polycomb-Associated Non-Coding RNAs.
MA598548 - JP 2018138019-A/170474: Polycomb-Associated Non-Coding RNAs.
MA598547 - JP 2018138019-A/170473: Polycomb-Associated Non-Coding RNAs.
MA598546 - JP 2018138019-A/170472: Polycomb-Associated Non-Coding RNAs.
MA598544 - JP 2018138019-A/170470: Polycomb-Associated Non-Coding RNAs.
MA598543 - JP 2018138019-A/170469: Polycomb-Associated Non-Coding RNAs.
MA442767 - JP 2018138019-A/14693: Polycomb-Associated Non-Coding RNAs.

-  Biochemical and Signaling Pathways
  BioCarta from NCI Cancer Genome Anatomy Project
h_arfPathway - Tumor Suppressor Arf Inhibits Ribosomal Biogenesis

Reactome (by CSHL, EBI, and GO)

Protein O95602 (Reactome details) participates in the following event(s):

R-HSA-73865 Assembly of RNA Polymerase I Holoenzyme (human)
R-HSA-73757 Binding of RRN3 to RNA Polymerase I
R-HSA-5250947 B-WICH complex binds rDNA promoter
R-HSA-73758 Recruitment of Active RNA Polymerase I to SL1:phos.UBF-1:rDNA Promoter
R-HSA-74994 Polymerase I Transcription Complex/Nascent Pre rRNA Complex pauses at the TTF-I:Sal Box
R-HSA-73769 Loss of Rrn3 from RNA Polymerase I promoter escape complex
R-HSA-74992 Dissociation of PTRF:Polymerase I/Nascent Pre rRNA Complex:TTF-I:Sal Box
R-HSA-5250930 B-WICH recruits histone acetyltransferases
R-HSA-74993 PTRF Binds the Polymerase I Transcription Complex/Nascent Pre rRNA Complex paused at the TTF-I:Sal Box
R-HSA-74986 Elongation of pre-rRNA transcript
R-HSA-427366 Transcription of intergenic spacer of the rRNA gene
R-HSA-5250938 B-WICH:histone acetyltransferase acetylates histone H3 at lysine-9
R-HSA-73762 RNA Polymerase I Transcription Initiation
R-HSA-5250924 B-WICH complex positively regulates rRNA expression
R-HSA-73854 RNA Polymerase I Promoter Clearance
R-HSA-73863 RNA Polymerase I Transcription Termination
R-HSA-73772 RNA Polymerase I Promoter Escape
R-HSA-5250913 Positive epigenetic regulation of rRNA expression
R-HSA-73864 RNA Polymerase I Transcription
R-HSA-73777 RNA Polymerase I Chain Elongation
R-HSA-427413 NoRC negatively regulates rRNA expression
R-HSA-212165 Epigenetic regulation of gene expression
R-HSA-74160 Gene expression (Transcription)
R-HSA-5250941 Negative epigenetic regulation of rRNA expression

-  Other Names for This Gene
  Alternate Gene Symbols: B7Z7T0, D6W5M0, ENST00000263857.1, ENST00000263857.10, ENST00000263857.2, ENST00000263857.3, ENST00000263857.4, ENST00000263857.5, ENST00000263857.6, ENST00000263857.7, ENST00000263857.8, ENST00000263857.9, NM_015425, O95602, Q0VG05, Q9UEH0, Q9UFT9, RPA1_HUMAN, uc317hmz.1, uc317hmz.2
UCSC ID: ENST00000263857.11_12
RefSeq Accession: NM_015425.6
Protein: O95602 (aka RPA1_HUMAN)

-  Gene Model Information
  Click here for a detailed description of the fields of the table above.

-  Methods, Credits, and Use Restrictions
  Click here for details on how this gene model was made and data restrictions if any.