cas12.py

from keras import Model
from keras.layers import Input
from keras.layers import Multiply
from keras.layers import Dense, Dropout, Activation, Flatten
from keras.layers import Convolution1D, AveragePooling1D
import pandas as pd
import numpy as np
import keras
import requests
from functools import reduce
from operator import add
from Bio.SeqRecord import SeqRecord
from Bio.SeqFeature import SeqFeature, FeatureLocation
from Bio.Seq import Seq
from Bio import SeqIO

ntmap = {'A': (1, 0, 0, 0),
         'C': (0, 1, 0, 0),
         'G': (0, 0, 1, 0),
         'T': (0, 0, 0, 1)
         }

def get_seqcode(seq):
    return np.array(reduce(add, map(lambda c: ntmap[c], seq.upper()))).reshape((1, len(seq), -1))

def Seq_DeepCpf1_model(input_shape):
  Seq_deepCpf1_Input_SEQ = Input(shape=input_shape)
  Seq_deepCpf1_C1 = Convolution1D(80, 5, activation='relu')(Seq_deepCpf1_Input_SEQ)
  Seq_deepCpf1_P1 = AveragePooling1D(2)(Seq_deepCpf1_C1)
  Seq_deepCpf1_F = Flatten()(Seq_deepCpf1_P1)
  Seq_deepCpf1_DO1 = Dropout(0.3)(Seq_deepCpf1_F)
  Seq_deepCpf1_D1 = Dense(80, activation='relu')(Seq_deepCpf1_DO1)
  Seq_deepCpf1_DO2 = Dropout(0.3)(Seq_deepCpf1_D1)
  Seq_deepCpf1_D2 = Dense(40, activation='relu')(Seq_deepCpf1_DO2)
  Seq_deepCpf1_DO3 = Dropout(0.3)(Seq_deepCpf1_D2)
  Seq_deepCpf1_D3 = Dense(40, activation='relu')(Seq_deepCpf1_DO3)
  Seq_deepCpf1_DO4 = Dropout(0.3)(Seq_deepCpf1_D3)
  Seq_deepCpf1_Output = Dense(1, activation='linear')(Seq_deepCpf1_DO4)
  Seq_deepCpf1 = Model(inputs=[Seq_deepCpf1_Input_SEQ], outputs=[Seq_deepCpf1_Output])
  return Seq_deepCpf1

# seq-ca model (DeepCpf1)
def DeepCpf1_model(input_shape):
  DeepCpf1_Input_SEQ = Input(shape=input_shape)
  DeepCpf1_C1 = Convolution1D(80, 5, activation='relu')(DeepCpf1_Input_SEQ)
  DeepCpf1_P1 = AveragePooling1D(2)(DeepCpf1_C1)
  DeepCpf1_F = Flatten()(DeepCpf1_P1)
  DeepCpf1_DO1 = Dropout(0.3)(DeepCpf1_F)
  DeepCpf1_D1 = Dense(80, activation='relu')(DeepCpf1_DO1)
  DeepCpf1_DO2 = Dropout(0.3)(DeepCpf1_D1)
  DeepCpf1_D2 = Dense(40, activation='relu')(DeepCpf1_DO2)
  DeepCpf1_DO3 = Dropout(0.3)(DeepCpf1_D2)
  DeepCpf1_D3_SEQ = Dense(40, activation='relu')(DeepCpf1_DO3)
  DeepCpf1_Input_CA = Input(shape=(1,))
  DeepCpf1_D3_CA = Dense(40, activation='relu')(DeepCpf1_Input_CA)
  DeepCpf1_M = Multiply()([DeepCpf1_D3_SEQ, DeepCpf1_D3_CA])
  DeepCpf1_DO4 = Dropout(0.3)(DeepCpf1_M)
  DeepCpf1_Output = Dense(1, activation='linear')(DeepCpf1_DO4)
  DeepCpf1 = Model(inputs=[DeepCpf1_Input_SEQ, DeepCpf1_Input_CA], outputs=[DeepCpf1_Output])
  return DeepCpf1

def fetch_ensembl_transcripts(gene_symbol):
    url = f"https://rest.ensembl.org/lookup/symbol/homo_sapiens/{gene_symbol}?expand=1;content-type=application/json"
    response = requests.get(url)
    if response.status_code == 200:
        gene_data = response.json()
        if 'Transcript' in gene_data:
            return gene_data['Transcript']
        else:
            print("No transcripts found for gene:", gene_symbol)
            return None
    else:
        print(f"Error fetching gene data from Ensembl: {response.text}")
        return None

def fetch_ensembl_sequence(transcript_id):
    url = f"https://rest.ensembl.org/sequence/id/{transcript_id}?content-type=application/json"
    response = requests.get(url)
    if response.status_code == 200:
        sequence_data = response.json()
        if 'seq' in sequence_data:
            return sequence_data['seq']
        else:
            print("No sequence found for transcript:", transcript_id)
            return None
    else:
        print(f"Error fetching sequence data from Ensembl: {response.text}")
        return None


def find_crispr_targets(sequence, chr, start, strand, pam="TTTN", target_length=34):
    targets = []
    len_sequence = len(sequence)

    for i in range(len_sequence - target_length + 1):
        target_seq = sequence[i:i + target_length]
        if target_seq[4:7] == 'TTT':
            tar_start = start + i
            tar_end = start + i + target_length
            gRNA = target_seq[8:28]
            targets.append([target_seq, gRNA, chr, str(tar_start), str(tar_end), str(strand)])
    return targets

def format_prediction_output(targets, seq_deepCpf1):
    formatted_data = []
    for target in targets:
        # Predict
        encoded_seq = get_seqcode(target[0])  # 'target' seems to be the full sequence including PAM
        prediction = seq_deepCpf1.predict(encoded_seq)
        # Format output
        gRNA = target[1]  # gRNA is presumably the guide RNA sequence
        chr = target[2]  # Chromosome
        start = target[3]  # Start position
        end = target[4]  # End position
        strand = target[5]  # Strand
        target_seq = target[0]  # Full target sequence including PAM
        formatted_data.append([chr, start, end, strand, target_seq, gRNA, prediction[0][0]])
    return formatted_data

def process_gene(gene_symbol, model_path):
    transcripts = fetch_ensembl_transcripts(gene_symbol)
    all_data = []
    gene_sequence = ''  # Initialize an empty string for the gene sequence

    # Load the model
    seq_deepCpf1 = Seq_DeepCpf1_model(input_shape=(34, 4))
    seq_deepCpf1.load_weights(model_path)

    if transcripts:
        for transcript in transcripts:
            transcript_id = transcript['id']
            chr = transcript.get('seq_region_name', 'unknown')
            start = transcript.get('start', 0)
            strand = transcript.get('strand', 'unknown')
            # Fetch the sequence here and concatenate if multiple transcripts
            gene_sequence += fetch_ensembl_sequence(transcript_id) or ''

            if gene_sequence:
                targets = find_crispr_targets(gene_sequence, chr, start, strand)
                if targets:
                    formatted_data = format_prediction_output(targets, seq_deepCpf1)
                    all_data.extend(formatted_data)
    else:
        print("Failed to retrieve transcripts.")

    return all_data, gene_sequence


def create_genbank_features(formatted_data):
    features = []
    for data in formatted_data:
        try:
            # Attempt to convert start and end positions to integers
            start = int(data[1])
            end = int(data[2])
        except ValueError as e:
            # Log the error and skip this iteration if conversion fails
            print(f"Error converting start/end to int: {data[1]}, {data[2]} - {e}")
            continue  # Skip this iteration

        # Proceed as normal if conversion is successful
        strand = 1 if data[3] == '+' else -1
        location = FeatureLocation(start=start, end=end, strand=strand)
        feature = SeqFeature(location=location, type="misc_feature", qualifiers={
            'label': data[5],  # gRNA as label
            'note': f"Prediction: {data[6]}"  # Prediction score in note
        })
        features.append(feature)
    return features

def generate_genbank_file_from_data(formatted_data, gene_sequence, gene_symbol, output_path):
    features = create_genbank_features(formatted_data)
    record = SeqRecord(Seq(gene_sequence), id=gene_symbol, name=gene_symbol,
                       description='CRISPR Cas12 predicted targets', features=features)
    record.annotations["molecule_type"] = "DNA"
    SeqIO.write(record, output_path, "genbank")

def generate_bed_file_from_data(formatted_data, output_path):
    with open(output_path, 'w') as bed_file:
        for data in formatted_data:
            chrom = data[0]
            start = data[1]
            end = data[2]
            strand = data[3]
            gRNA = data[5]
            score = data[6]
            bed_file.write(f"{chrom}\t{start}\t{end}\t{gRNA}\t{score}\t{strand}\n")