def construct_names(gene_ID, transcript_ID, prefix, n_places):
    """ Create a gene and transcript name using the TALON IDs.
        The n_places variable indicates how many characters long the numeric
        part of the name should be. """

    gene_ID_str = str(gene_ID).zfill(n_places)
    gene_name = prefix + "G" + gene_ID_str

    transcript_ID_str = str(transcript_ID).zfill(n_places)
    transcript_name = prefix + "T" + transcript_ID_str

    return gene_name, transcript_name