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trimest |
Function
Trim poly-A tails off EST sequencesDescription
EST and mRNA sequences often have poly-A tails at the end of them. This utility removes those poly-A tails.EST sequences are often the reverse complement of the corresponding mRNA's forward sense and have poly-T tails at their 5' end. By default, this program also detects and removes these and writes out the reverse complement of the sequence.
trimest is not infallible. There are often repeats of 'A' (or 'T') in a sequence that just happen by chance to occur at the 3' (or 5') end of the EST sequence. trimest has no way of determining if the A's it finds are part of a real poly-A tail or are a part of the transcribed genomic sequence. It removes any apparent poly-A tails that match its criteria for a poly-A tail.
trimest looks for a repeat of at least '-minlength' A's at the 3' end (and, by default, '-minlength' T's at the 5' end). If there are an apparent 5' poly-T tail and a poly-A tail, then it removes whichever is the longer of the two.
By default, it will allow '-mismatches' non-A (or non-T) bases in the tail. If a mismatch is found, then there has to be at least '-minlength' A's (or T's) past the mismatch (working from the end) for the mismatch to be considered part of the tail. If '-mismatches' is greater than 1 then that number of contiguous non-A (or non-T) bases will be allowed as part of the tail.
If a 5' poly-T tail is found, then the sequence will be optionally reverse-complemented when it is written out.
If a poly-A tail is reomved then '[poly-A tail removed]' is appended to the description of the sequence. If poly-T is removed, then '[poly-T tail removed]' is appended and if the sequence is reversed, '[reverse complement]' is appended.
Usage
Here is a sample session with trimest
% trimest tembl:hsfau hsfau.seq Trim poly-A tails off EST sequences |
Go to the input files for this example
Go to the output files for this example
Command line arguments
Standard (Mandatory) qualifiers:
[-sequence] seqall Sequence database USA
[-outseq] seqoutall Output sequence(s) USA
Additional (Optional) qualifiers:
-minlength integer This is the minimum length that a poly-A (or
poly-T) tail must have before it is
removed. If there are mismatches in the tail
than there must be at least this length of
poly-A tail before the mismatch for the
mismatch to be considered part of the tail.
-mismatches integer If there are this number or fewer contiguous
non-A bases in a poly-A tail then, if there
are '-minlength' 'A' bases before them,
they will be considered part of the tail and
removed .
For example the terminal 4 A's of GCAGAAAA
would be removed with the default values of
-minlength=4 and -mismatches=1 (There are
not at least 4 A's before the last 'G' and
so only the A's after it are considered to
be part of the tail). The terminal 9 bases
of GCAAAAGAAAA would be removed; There are
at least -minlength A's preceeding the last
'G', so it is part of the tail.
-[no]reverse boolean When a poly-T region at the 5' end of the
sequence is found and removed, it is likely
that the sequence is in the reverse sense.
This option will change the sequence to the
forward sense when it is written out. If
this option is not set, then the sense will
not be changed.
-tolower toggle The poly-A region can be 'masked' by
converting the sequence characters to
lower-case. Some non-EMBOSS programs e.g.
fasta can interpret this as a masked region.
The sequence is unchanged apart from the
case change. You might like to ensure that
the whole sequence is in upper-case before
masking the specified regions to lower-case
by using the '-supper' sequence qualifier.
Advanced (Unprompted) qualifiers:
-[no]fiveprime boolean If this is set true, then the 5' end of teh
sequence is inspected for poly-T tails.
These will be removed if they are longer
than any 3' poly-A tails. If this is false,
then the 5' end is ignored.
Associated qualifiers:
"-sequence" associated qualifiers
-sbegin1 integer Start of each sequence to be used
-send1 integer End of each sequence to be used
-sreverse1 boolean Reverse (if DNA)
-sask1 boolean Ask for begin/end/reverse
-snucleotide1 boolean Sequence is nucleotide
-sprotein1 boolean Sequence is protein
-slower1 boolean Make lower case
-supper1 boolean Make upper case
-sformat1 string Input sequence format
-sdbname1 string Database name
-sid1 string Entryname
-ufo1 string UFO features
-fformat1 string Features format
-fopenfile1 string Features file name
"-outseq" associated qualifiers
-osformat2 string Output seq format
-osextension2 string File name extension
-osname2 string Base file name
-osdirectory2 string Output directory
-osdbname2 string Database name to add
-ossingle2 boolean Separate file for each entry
-oufo2 string UFO features
-offormat2 string Features format
-ofname2 string Features file name
-ofdirectory2 string Output directory
General qualifiers:
-auto boolean Turn off prompts
-stdout boolean Write standard output
-filter boolean Read standard input, write standard output
-options boolean Prompt for standard and additional values
-debug boolean Write debug output to program.dbg
-verbose boolean Report some/full command line options
-help boolean Report command line options. More
information on associated and general
qualifiers can be found with -help -verbose
-warning boolean Report warnings
-error boolean Report errors
-fatal boolean Report fatal errors
-die boolean Report deaths
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| Standard (Mandatory) qualifiers | Allowed values | Default | |
|---|---|---|---|
| [-sequence] (Parameter 1) |
Sequence database USA | Readable sequence(s) | Required |
| [-outseq] (Parameter 2) |
Output sequence(s) USA | Writeable sequence(s) | <sequence>.format |
| Additional (Optional) qualifiers | Allowed values | Default | |
| -minlength | This is the minimum length that a poly-A (or poly-T) tail must have before it is removed. If there are mismatches in the tail than there must be at least this length of poly-A tail before the mismatch for the mismatch to be considered part of the tail. | Integer 1 or more | 4 |
| -mismatches | If there are this number or fewer contiguous non-A bases in a poly-A tail then, if there are '-minlength' 'A' bases before them, they will be considered part of the tail and removed . For example the terminal 4 A's of GCAGAAAA would be removed with the default values of -minlength=4 and -mismatches=1 (There are not at least 4 A's before the last 'G' and so only the A's after it are considered to be part of the tail). The terminal 9 bases of GCAAAAGAAAA would be removed; There are at least -minlength A's preceeding the last 'G', so it is part of the tail. | Integer 0 or more | 1 |
| -[no]reverse | When a poly-T region at the 5' end of the sequence is found and removed, it is likely that the sequence is in the reverse sense. This option will change the sequence to the forward sense when it is written out. If this option is not set, then the sense will not be changed. | Boolean value Yes/No | Yes |
| -tolower | The poly-A region can be 'masked' by converting the sequence characters to lower-case. Some non-EMBOSS programs e.g. fasta can interpret this as a masked region. The sequence is unchanged apart from the case change. You might like to ensure that the whole sequence is in upper-case before masking the specified regions to lower-case by using the '-supper' sequence qualifier. | Toggle value Yes/No | No |
| Advanced (Unprompted) qualifiers | Allowed values | Default | |
| -[no]fiveprime | If this is set true, then the 5' end of teh sequence is inspected for poly-T tails. These will be removed if they are longer than any 3' poly-A tails. If this is false, then the 5' end is ignored. | Boolean value Yes/No | Yes |
Input file format
trimest reads the USA of one or more normal nucleic acid sequences.Input files for usage example
'tembl:hsfau' is a sequence entry in the example nucleic acid database 'tembl'
Database entry: tembl:hsfau
ID HSFAU standard; RNA; HUM; 518 BP.
XX
AC X65923;
XX
SV X65923.1
XX
DT 13-MAY-1992 (Rel. 31, Created)
DT 23-SEP-1993 (Rel. 37, Last updated, Version 10)
XX
DE H.sapiens fau mRNA
XX
KW fau gene.
XX
OS Homo sapiens (human)
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC Eutheria; Primates; Catarrhini; Hominidae; Homo.
XX
RN [1]
RP 1-518
RA Michiels L.M.R.;
RT ;
RL Submitted (29-APR-1992) to the EMBL/GenBank/DDBJ databases.
RL L.M.R. Michiels, University of Antwerp, Dept of Biochemistry,
RL Universiteisplein 1, 2610 Wilrijk, BELGIUM
XX
RN [2]
RP 1-518
RX MEDLINE; 93368957.
RA Michiels L., Van der Rauwelaert E., Van Hasselt F., Kas K., Merregaert J.;
RT " fau cDNA encodes a ubiquitin-like-S30 fusion protein and is expressed as
RT an antisense sequences in the Finkel-Biskis-Reilly murine sarcoma virus";
RL Oncogene 8:2537-2546(1993).
XX
DR SWISS-PROT; P35544; UBIM_HUMAN.
DR SWISS-PROT; Q05472; RS30_HUMAN.
XX
FH Key Location/Qualifiers
FH
FT source 1..518
FT /chromosome="11q"
FT /db_xref="taxon:9606"
FT /organism="Homo sapiens"
FT /tissue_type="placenta"
FT /clone_lib="cDNA"
FT /clone="pUIA 631"
FT /map="13"
FT misc_feature 57..278
FT /note="ubiquitin like part"
FT CDS 57..458
FT /db_xref="SWISS-PROT:P35544"
FT /db_xref="SWISS-PROT:Q05472"
FT /gene="fau"
FT /protein_id="CAA46716.1"
FT /translation="MQLFVRAQELHTFEVTGQETVAQIKAHVASLEGIAPEDQVVLLAG
FT APLEDEATLGQCGVEALTTLEVAGRMLGGKVHGSLARAGKVRGQTPKVAKQEKKKKKTG
FT RAKRRMQYNRRFVNVVPTFGKKKGPNANS"
FT misc_feature 98..102
FT /note="nucleolar localization signal"
FT misc_feature 279..458
FT /note="S30 part"
FT polyA_signal 484..489
FT polyA_site 509
XX
SQ Sequence 518 BP; 125 A; 139 C; 148 G; 106 T; 0 other;
ttcctctttc tcgactccat cttcgcggta gctgggaccg ccgttcagtc gccaatatgc 60
agctctttgt ccgcgcccag gagctacaca ccttcgaggt gaccggccag gaaacggtcg 120
cccagatcaa ggctcatgta gcctcactgg agggcattgc cccggaagat caagtcgtgc 180
tcctggcagg cgcgcccctg gaggatgagg ccactctggg ccagtgcggg gtggaggccc 240
tgactaccct ggaagtagca ggccgcatgc ttggaggtaa agttcatggt tccctggccc 300
gtgctggaaa agtgagaggt cagactccta aggtggccaa acaggagaag aagaagaaga 360
agacaggtcg ggctaagcgg cggatgcagt acaaccggcg ctttgtcaac gttgtgccca 420
cctttggcaa gaagaagggc cccaatgcca actcttaagt cttttgtaat tctggctttc 480
tctaataaaa aagccactta gttcagtcaa aaaaaaaa 518
//
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Output file format
Output files for usage example
File: hsfau.seq
>HSFAU X65923.1 H.sapiens fau mRNA [poly-A tail removed] ttcctctttctcgactccatcttcgcggtagctgggaccgccgttcagtcgccaatatgc agctctttgtccgcgcccaggagctacacaccttcgaggtgaccggccaggaaacggtcg cccagatcaaggctcatgtagcctcactggagggcattgccccggaagatcaagtcgtgc tcctggcaggcgcgcccctggaggatgaggccactctgggccagtgcggggtggaggccc tgactaccctggaagtagcaggccgcatgcttggaggtaaagttcatggttccctggccc gtgctggaaaagtgagaggtcagactcctaaggtggccaaacaggagaagaagaagaaga agacaggtcgggctaagcggcggatgcagtacaaccggcgctttgtcaacgttgtgccca cctttggcaagaagaagggccccaatgccaactcttaagtcttttgtaattctggctttc tctaataaaaaagccacttagttcagtc |
The output is a set of sequences with the poly-A (or poly-T) tails removed. If a sequence had a 5' poly-T tail then the resulting sequence is reverse-complemented by default. The description line has a comment appended about the changes made to the sequence.
Data files
None.Notes
None.References
None.Warnings
It will trim any run of more than -minlength A's or T's at the 3' or 5' end, whether or not they are a true poly-A tail.Diagnostic Error Messages
None.Exit status
It always exits with status 0.Known bugs
None.See also
| Program name | Description |
|---|---|
| biosed | Replace or delete sequence sections |
| codcopy | Reads and writes a codon usage table |
| cutseq | Removes a specified section from a sequence |
| degapseq | Removes gap characters from sequences |
| descseq | Alter the name or description of a sequence |
| entret | Reads and writes (returns) flatfile entries |
| extractfeat | Extract features from a sequence |
| extractseq | Extract regions from a sequence |
| listor | Write a list file of the logical OR of two sets of sequences |
| maskfeat | Mask off features of a sequence |
| maskseq | Mask off regions of a sequence |
| newseq | Type in a short new sequence |
| noreturn | Removes carriage return from ASCII files |
| notseq | Exclude a set of sequences and write out the remaining ones |
| nthseq | Writes one sequence from a multiple set of sequences |
| pasteseq | Insert one sequence into another |
| revseq | Reverse and complement a sequence |
| seqret | Reads and writes (returns) sequences |
| seqretsplit | Reads and writes (returns) sequences in individual files |
| skipseq | Reads and writes (returns) sequences, skipping first few |
| splitter | Split a sequence into (overlapping) smaller sequences |
| trimseq | Trim ambiguous bits off the ends of sequences |
| union | Reads sequence fragments and builds one sequence |
| vectorstrip | Strips out DNA between a pair of vector sequences |
| yank | Reads a sequence range, appends the full USA to a list file |
Author(s)
Gary Williams (gwilliam © rfcgr.mrc.ac.uk)MRC Rosalind Franklin Centre for Genomics Research Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SB, UK