diff translate_bed_sequences.py @ 0:d328db400280 draft default tip

Uploaded

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/translate_bed_sequences.py	Wed Feb 05 09:27:54 2014 -0500
@@ -0,0 +1,255 @@
+#!/usr/bin/env python
+"""
+#
+#------------------------------------------------------------------------------
+#                         University of Minnesota
+#         Copyright 2014, Regents of the University of Minnesota
+#------------------------------------------------------------------------------
+# Author:
+#
+#  James E Johnson
+#
+#------------------------------------------------------------------------------
+"""
+
+"""
+Input:  BED file (12 column) + 13th sequence column appended by extract_genomic_dna
+Output: Fasta of 3-frame translations of the spliced sequence
+  
+"""
+
+import sys,re,os.path
+import optparse
+from optparse import OptionParser
+from Bio.Seq import reverse_complement, transcribe, back_transcribe, translate
+
+class BedEntry( object ):
+  def __init__(self, line):
+    self.line = line
+    try:
+      (chrom,chromStart,chromEnd,name,score,strand,thickStart,thickEnd,itemRgb,blockCount,blockSizes,blockStarts,seq) = line.split('\t')[0:13]
+      self.chrom = chrom
+      self.chromStart = int(chromStart)
+      self.chromEnd = int(chromEnd)
+      self.name = name
+      self.score = int(score)
+      self.strand = strand
+      self.thickStart = int(thickStart)
+      self.thickEnd = int(thickEnd)
+      self.itemRgb = itemRgb
+      self.blockCount = int(blockCount)
+      self.blockSizes = [int(x) for x in blockSizes.split(',')]
+      self.blockStarts = [int(x) for x in blockStarts.split(',')]
+      self.seq = seq
+    except Exception, e:
+      print >> sys.stderr, "Unable to read Bed entry" % e
+      exit(1)
+  def get_splice_junctions(self): 
+    splice_juncs = []
+    for i in range(self.blockCount  - 1):
+      splice_junc = "%s:%d_%d" % (self.chrom, self.chromStart + self.blockSizes[i], self.chromStart + self.blockStarts[i+1])
+      splice_juncs.append(splice_junc)
+    return splice_juncs
+  def get_exon_seqs(self):
+    exons = []
+    for i in range(self.blockCount):
+      # splice_junc = "%s:%d_%d" % (self.chrom, self.chromStart + self.blockSizes[i], self.chromStart + self.blockStarts[i+1])
+      exons.append(self.seq[self.blockStarts[i]:self.blockStarts[i] + self.blockSizes[i]])
+    if self.strand == '-':  #reverse complement
+      exons.reverse()
+      for i,s in enumerate(exons):
+        exons[i] = reverse_complement(s)
+    return exons
+  def get_spliced_seq(self):
+    seq = ''.join(self.get_exon_seqs())
+    return seq
+  def get_translation(self,sequence=None):
+    translation = None
+    seq = sequence if sequence else self.get_spliced_seq()
+    if seq:
+      seqlen = len(seq) / 3 * 3;
+      if seqlen >= 3:
+        translation = translate(seq[:seqlen])
+    return translation
+  def get_translations(self):
+    translations = []
+    seq = self.get_spliced_seq()
+    if seq:
+      for i in range(3):
+        translation = self.get_translation(sequence=seq[i:])
+        if translation:
+          translations.append(translation)
+    return translations
+  ## [[start,end,seq],[start,end,seq],[start,end,seq]]
+  ## filter: ignore translation if stop codon in first exon after ignore_left_bp
+  def get_filterd_translations(self,untrimmed=False,filtering=True,ignore_left_bp=0,ignore_right_bp=0):
+    translations = [None,None,None]
+    seq = self.get_spliced_seq()
+    ignore = (ignore_left_bp if self.strand == '+' else ignore_right_bp) / 3
+    block_sum = sum(self.blockSizes)
+    exon_sizes = self.blockSizes
+    if self.strand == '-':
+      exon_sizes.reverse()
+    splice_sites = [sum(exon_sizes[:x]) / 3 for x in range(1,len(exon_sizes))]
+    junc = splice_sites[0] if len(splice_sites) > 0 else exon_sizes[0]
+    if seq:
+      for i in range(3):
+        translation = self.get_translation(sequence=seq[i:])
+        if translation:
+          tstart = 0
+          tstop = len(translation)
+          if not untrimmed:
+            tstart = translation.rfind('*',0,junc) + 1
+            stop = translation.find('*',junc)
+            tstop = stop if stop >= 0 else len(translation)
+          if filtering and tstart > ignore:
+            continue
+          trimmed = translation[tstart:tstop]
+          #get genomic locations for start and end 
+          offset = (block_sum - i) % 3
+          if self.strand == '+':
+            chromStart = self.chromStart + i + (tstart * 3)
+            chromEnd = self.chromEnd - offset - (len(translation) - tstop) * 3
+          else:
+            chromStart = self.chromStart + offset + (len(translation) - tstop) * 3
+            chromEnd = self.chromEnd - i - (tstart * 3)
+          translations[i] = [chromStart,chromEnd,trimmed]
+    return translations
+  def get_seq_id(self,seqtype='unk:unk',reference='',frame=None):
+    ## Ensembl fasta ID format
+    # >ID SEQTYPE:STATUS LOCATION GENE TRANSCRIPT
+    # >ENSP00000328693 pep:splice chromosome:NCBI35:1:904515:910768:1 gene:ENSG00000158815:transcript:ENST00000328693 gene_biotype:protein_coding transcript_biotype:protein_coding
+    frame_name = ''
+    chromStart = self.chromStart
+    chromEnd = self.chromEnd
+    strand = 1 if self.strand == '+' else -1
+    if frame != None:
+      block_sum = sum(self.blockSizes)
+      offset = (block_sum - frame) % 3
+      frame_name = '_' + str(frame + 1)
+      if self.strand == '+':
+        chromStart += frame
+        chromEnd -= offset
+      else:
+        chromStart += offset
+        chromEnd -= frame
+    location = "chromosome:%s:%s:%s:%s:%s" % (reference,self.chrom,chromStart,chromEnd,strand)
+    seq_id = "%s%s %s %s" % (self.name,frame_name,seqtype,location)
+    return seq_id
+  def get_line(self, start_offset = 0, end_offset = 0):
+    if start_offset or end_offset:
+      s_offset = start_offset if start_offset else 0
+      e_offset = end_offset if end_offset else 0
+      if s_offset > self.chromStart:
+        s_offset = self.chromStart
+      chrStart = self.chromStart - s_offset
+      chrEnd = self.chromEnd + e_offset
+      blkSizes = self.blockSizes
+      blkSizes[0] += s_offset
+      blkSizes[-1] += e_offset
+      blkStarts = self.blockStarts
+      for i in range(1,self.blockCount):
+        blkStarts[i] += s_offset
+      items = [str(x) for x in [self.chrom,chrStart,chrEnd,self.name,self.score,self.strand,self.thickStart,self.thickEnd,self.itemRgb,self.blockCount,','.join([str(x) for x in blkSizes]),','.join([str(x) for x in blkStarts])]]
+      return '\t'.join(items) + '\n'
+    return self.line
+
+def __main__():
+  #Parse Command Line
+  parser = optparse.OptionParser()
+  parser.add_option( '-i', '--input', dest='input', help='BED file (tophat junctions.bed) with sequence column added' )
+  parser.add_option( '-o', '--output', dest='output', help='Translations of spliced sequence')
+  parser.add_option( '-b', '--bed_format', dest='bed_format', action='store_true', default=False, help='Append translations to bed file instead of fasta'  )
+  parser.add_option( '-S', '--seqtype', dest='seqtype', default='pep:splice', help='SEQTYPE:STATUS for fasta ID line'  )
+  parser.add_option( '-R', '--reference', dest='reference', default=None, help='Genome Reference Name for fasta ID location '  )
+  parser.add_option( '-Q', '--score_name', dest='score_name', default=None, help='include in the fasta ID line score_name:score '  )
+  parser.add_option( '-l', '--leading_bp', dest='leading_bp', type='int', default=None, help='leading number of base pairs to ignore when filtering' )
+  parser.add_option( '-t', '--trailing_bp', dest='trailing_bp', type='int', default=None, help='trailing number of base pairs to ignore when filtering' )
+  parser.add_option( '-U', '--unfiltered', dest='filtering', action='store_false', default=True, help='Do NOT filterout translation with stop codon in the first exon'  )
+  parser.add_option( '-u', '--untrimmed', dest='untrimmed', action='store_true', default=False, help='Do NOT trim from splice site to stop codon'  )
+  parser.add_option( '-L', '--min_length', dest='min_length', type='int', default=None, help='Minimun length (to first stop codon)'  )
+  parser.add_option( '-M', '--max_stop_codons', dest='max_stop_codons', type='int', default=None, help='Filter out translations with more than max_stop_codons'  )
+  parser.add_option( '-d', '--debug', dest='debug', action='store_true', default=False, help='Turn on wrapper debugging to stdout'  )
+  (options, args) = parser.parse_args()
+  # Input files
+  if options.input != None:
+    try:
+      inputPath = os.path.abspath(options.input)
+      inputFile = open(inputPath, 'r')
+    except Exception, e:
+      print >> sys.stderr, "failed: %s" % e
+      exit(2)
+  else:
+    inputFile = sys.stdin
+  # Output files
+  outFile = None
+  if options.output == None:
+    #write to stdout
+    outFile = sys.stdout
+  else:
+    try:
+      outPath = os.path.abspath(options.output)
+      outFile = open(outPath, 'w')
+    except Exception, e:
+      print >> sys.stderr, "failed: %s" % e
+      exit(3)
+  leading_bp = 0
+  trailing_bp = 0
+  if options.leading_bp:
+    if options.leading_bp >= 0:
+      leading_bp = options.leading_bp
+    else:
+      print >> sys.stderr, "failed: leading_bp must be positive"
+      exit(5)
+  if options.trailing_bp:
+    if  options.trailing_bp >= 0:
+      trailing_bp = options.trailing_bp
+    else:
+      print >> sys.stderr, "failed: trailing_bp must be positive"
+      exit(5)
+  # Scan bed file 
+  try:
+    for i, line in enumerate( inputFile ):
+      if line.startswith('track'):
+        if outFile and options.bed_format:
+          outFile.write(line)
+        continue
+      entry = BedEntry(line)
+      strand = 1 if entry.strand == '+' else -1
+      translations = entry.get_translations()
+      if options.debug:
+        exon_seqs = entry.get_exon_seqs()
+        exon_sizes = [len(seq) for seq in exon_seqs]
+        splice_sites = [sum(exon_sizes[:x]) / 3 for x in range(1,len(exon_sizes))]
+        print >> sys.stderr, entry.name
+        print >> sys.stderr, line.rstrip('\r\n')
+        print >> sys.stderr, "exons:  %s" % exon_seqs
+        print >> sys.stderr, "%s" % splice_sites
+        for i,translation in enumerate(translations):
+          print >> sys.stderr, "frame %d:  %s" % (i+1,translation)
+          print >> sys.stderr, "splice:   %s" % (''.join(['^' if (((j*3)+i)/3) in splice_sites else '-' for j in range(len(translation))]))
+        print >> sys.stderr, ""
+      if options.bed_format:
+        tx_entry  = "%s\t%s\n" % (line.rstrip('\r\n'),'\t'.join(translations))
+        outFile.write(tx_entry)
+      else:
+        translations = entry.get_filterd_translations(untrimmed=options.untrimmed,filtering=options.filtering,ignore_left_bp=leading_bp,ignore_right_bp=trailing_bp)
+        for i,tx in enumerate(translations):
+          if tx:
+            (chromStart,chromEnd,translation) = tx
+            if options.min_length != None and len(translation) < options.min_length:
+              continue
+            if options.max_stop_codons != None and translation.count('*') > options.max_stop_codons:
+              continue
+            frame_name = '_%s' % (i + 1)
+            location = "chromosome:%s:%s:%s:%s:%s" % (options.reference,entry.chrom,chromStart,chromEnd,strand)
+            score = " %s:%s" % (options.score_name,entry.score) if options.score_name else ''
+            seq_id = "%s%s %s %s%s" % (entry.name,frame_name,options.seqtype,location, score)
+            outFile.write(">%s\n" % seq_id)
+            outFile.write(translation)
+            outFile.write('\n')
+  except Exception, e:
+    print >> sys.stderr, "failed: Error reading %s - %s" % (options.input if options.input else 'stdin',e)
+
+if __name__ == "__main__" : __main__()
+