Can anyone explain me the difference between exons and transcripts and is this true that coding sequence (CDS) are the exons. Another question about the splicing suppose if you have E1, E2 and E3 exons in the order of E1 E2 E3. Then after the splicing which combination will be possible.
E1E2E3, E1E3E2, E2E3E1, E2E1E3, E3E1E2 and E3E2E1
Hi Ankit,
In eukaryotics pre-mRNA will be processed to become mature mRNA through splicing. So basically what's done is cutting out introns and put the exon together. Transcripts is a result of transcription so in eukaryotics will refer to pre-mRNA. Although sometimes people using "mature transcripts" to define mRNA as well.
CDS refers to a coding DNA sequence. Therefore CDS containing exons and introns.
If you have E1E2E3 and there is an alternative splicing (assume there are only 3 exons in the gene and what you asked is not alternative polyadenylation site). Therefore the alternative exon must be E2 and the possible combination will be E1E3(exon skipping) or E1E2E3(exon inclusion).
If what happen is alternative polyadenylation site (meaning E3 is the alternative exon). The possible combination will be E1E2 or E1E2E3.
Hope it help!
Thank you Reymond for your answer. If CDS containing exons and introns then except UTR there is no difference between Gene and CDS. I downloaded GTF file from ENSEMBL and the information looks like. The new line start with Chr. I have one Gene in chromosome 1 from (11869-14409) and 2 transcript (11869-14409) and (12010- 13670) and 3 exon corresponds to first transcript and 6 exons corresponds to second transcript. So here one gene is making 2 transcript. So according to your conclusion here one gene is making 2 pre-mRNA. Am i right?Sorry for my little knowledge about the biology.
chr1 HAVANA gene 11869 14409 . + . gene_id "ENSG00000223972.5"; transcript_id "ENSG00000223972.5"; gene_type "transcribed_unprocessed_pseudogene"; gene_status "KNOWN"; gene_name "DDX11L1"; transcript_type "transcribed_unprocessed_pseudogene"; transcript_status "KNOWN"; transcript_name "DDX11L1"; level 2; havana_gene "OTTHUMG00000000961.2";
chr1 HAVANA transcript 11869 14409 . + . gene_id "ENSG00000223972.5"; transcript_id "ENST00000456328.2"; gene_type "transcribed_unprocessed_pseudogene"; gene_status "KNOWN"; gene_name "DDX11L1"; transcript_type "processed_transcript"; transcript_status "KNOWN"; transcript_name "DDX11L1-002"; level 2; tag "basic"; transcript_support_level "1"; havana_gene "OTTHUMG00000000961.2"; havana_transcript "OTTHUMT00000362751.1";
chr1 HAVANA exon 11869 12227 . + . gene_id "ENSG00000223972.5"; transcript_id "ENST00000456328.2"; gene_type "transcribed_unprocessed_pseudogene"; gene_status "KNOWN"; gene_name "DDX11L1"; transcript_type "processed_transcript"; transcript_status "KNOWN"; transcript_name "DDX11L1-002"; exon_number 1; exon_id "ENSE00002234944.1"; level 2; tag "basic"; transcript_support_level "1"; havana_gene "OTTHUMG00000000961.2"; havana_transcript "OTTHUMT00000362751.1";
chr1 HAVANA exon 12613 12721 . + . gene_id "ENSG00000223972.5"; transcript_id "ENST00000456328.2"; gene_type "transcribed_unprocessed_pseudogene"; gene_status "KNOWN"; gene_name "DDX11L1"; transcript_type "processed_transcript"; transcript_status "KNOWN"; transcript_name "DDX11L1-002"; exon_number 2; exon_id "ENSE00003582793.1"; level 2; tag "basic"; transcript_support_level "1"; havana_gene "OTTHUMG00000000961.2"; havana_transcript "OTTHUMT00000362751.1";
chr1 HAVANA exon 13221 14409 . + . gene_id "ENSG00000223972.5"; transcript_id "ENST00000456328.2"; gene_type "transcribed_unprocessed_pseudogene"; gene_status "KNOWN"; gene_name "DDX11L1"; transcript_type "processed_transcript"; transcript_status "KNOWN"; transcript_name "DDX11L1-002"; exon_number 3; exon_id "ENSE00002312635.1"; level 2; tag "basic"; transcript_support_level "1"; havana_gene "OTTHUMG00000000961.2"; havana_transcript "OTTHUMT00000362751.1";
chr1 HAVANA transcript 12010 13670 . + . gene_id "ENSG00000223972.5"; transcript_id "ENST00000450305.2"; gene_type "transcribed_unprocessed_pseudogene"; gene_status "KNOWN"; gene_name "DDX11L1"; transcript_type "transcribed_unprocessed_pseudogene"; transcript_status "KNOWN"; transcript_name "DDX11L1-001"; level 2; ont "PGO:0000005"; ont "PGO:0000019"; tag "basic"; transcript_support_level "NA"; havana_gene "OTTHUMG00000000961.2"; havana_transcript "OTTHUMT00000002844.2";
chr1 HAVANA exon 12010 12057 . + . gene_id "ENSG00000223972.5"; transcript_id "ENST00000450305.2"; gene_type "transcribed_unprocessed_pseudogene"; gene_status "KNOWN"; gene_name "DDX11L1"; transcript_type "transcribed_unprocessed_pseudogene"; transcript_status "KNOWN"; transcript_name "DDX11L1-001"; exon_number 1; exon_id "ENSE00001948541.1"; level 2; ont "PGO:0000005"; ont "PGO:0000019"; tag "basic"; transcript_support_level "NA"; havana_gene "OTTHUMG00000000961.2"; havana_transcript "OTTHUMT00000002844.2";
chr1 HAVANA exon 12179 12227 . + . gene_id "ENSG00000223972.5"; transcript_id "ENST00000450305.2"; gene_type "transcribed_unprocessed_pseudogene"; gene_status "KNOWN"; gene_name "DDX11L1"; transcript_type "transcribed_unprocessed_pseudogene"; transcript_status "KNOWN"; transcript_name "DDX11L1-001"; exon_number 2; exon_id "ENSE00001671638.2"; level 2; ont "PGO:0000005"; ont "PGO:0000019"; tag "basic"; transcript_support_level "NA"; havana_gene "OTTHUMG00000000961.2"; havana_transcript "OTTHUMT00000002844.2";
chr1 HAVANA exon 12613 12697 . + . gene_id "ENSG00000223972.5"; transcript_id "ENST00000450305.2"; gene_type "transcribed_unprocessed_pseudogene"; gene_status "KNOWN"; gene_name "DDX11L1"; transcript_type "transcribed_unprocessed_pseudogene"; transcript_status "KNOWN"; transcript_name "DDX11L1-001"; exon_number 3; exon_id "ENSE00001758273.2"; level 2; ont "PGO:0000005"; ont "PGO:0000019"; tag "basic"; transcript_support_level "NA"; havana_gene "OTTHUMG00000000961.2"; havana_transcript "OTTHUMT00000002844.2";
chr1 HAVANA exon 12975 13052 . + . gene_id "ENSG00000223972.5"; transcript_id "ENST00000450305.2"; gene_type "transcribed_unprocessed_pseudogene"; gene_status "KNOWN"; gene_name "DDX11L1"; transcript_type "transcribed_unprocessed_pseudogene"; transcript_status "KNOWN"; transcript_name "DDX11L1-001"; exon_number 4; exon_id "ENSE00001799933.2"; level 2; ont "PGO:0000005"; ont "PGO:0000019"; tag "basic"; transcript_support_level "NA"; havana_gene "OTTHUMG00000000961.2"; havana_transcript "OTTHUMT00000002844.2";
chr1 HAVANA exon 13221 13374 . + . gene_id "ENSG00000223972.5"; transcript_id "ENST00000450305.2"; gene_type "transcribed_unprocessed_pseudogene"; gene_status "KNOWN"; gene_name "DDX11L1"; transcript_type "transcribed_unprocessed_pseudogene"; transcript_status "KNOWN"; transcript_name "DDX11L1-001"; exon_number 5; exon_id "ENSE00001746346.2"; level 2; ont "PGO:0000005"; ont "PGO:0000019"; tag "basic"; transcript_support_level "NA"; havana_gene "OTTHUMG00000000961.2"; havana_transcript "OTTHUMT00000002844.2";
chr1 HAVANA exon 13453 13670 . + . gene_id "ENSG00000223972.5"; transcript_id "ENST00000450305.2"; gene_type "transcribed_unprocessed_pseudogene"; gene_status "KNOWN"; gene_name "DDX11L1"; transcript_type "transcribed_unprocessed_pseudogene"; transcript_status "KNOWN"; transcript_name "DDX11L1-001"; exon_number 6; exon_id "ENSE00001863096.1"; level 2; ont "PGO:0000005"; ont "PGO:0000019"; tag "basic"; transcript_support_level "NA"; havana_gene "OTTHUMG00000000961.2"; havana_transcript "OTTHUMT00000002844.2";
Hi Ankit,
Sorry for the confusion but now I know that you were asking about the terminology used in ENSEMBL.
So here unprocessed transcript means pre-mRNA and processed transcript means mRNA.
I can't really read the text it is too crowded.
But what is sure is one gene can only make one pre-mRNA (in eukaryotes), but then can derived to many different mRNAs through alternative splicing. So what you see here are 2 different mRNAs if you said there are 2 transcripts with different exons composition
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