GHRLOS overlaps a putative SEC1 3 isoform, SEC13-T , in an antisense manner. (A) Diagrammatic representation of GHRLOS, SEC13, and a novel SEC13 isoform, named SEC13-tentative (SEC13T). SEC13-T contains a novel terminal exon 9, termed exon 9b, which overlaps exon 4 of GHRLOS in an antisense manner. In the figure, exon 9b of SEC13-T is dotted to indicate that its complete 3' end has not been verified. Exons are represented as boxes and introns as horizontal lines. The locations of the primers employed to verify the SEC13T variant are displayed as arrows. SEC13 and SEC13-T GenBank accession numbers are shown. (B) Ethidium bromide stained agarose gel showing the verification of a SEC13-T EST [GenBank:BF931280] transcription by RT-PCR in prostate (RWPE-1 and RWPE-2) and prostate cancer derived cell lines (DU-145, PC3, LNCaP). NTC = no template control (water). M= DNA Molecular Weight Marker VI (Roche). Primer locations are depicted in (A). A 231 PCR fragment was amplified and sequenced, confirming the EST. (C) RNA and amino acid sequence of exon 9b of SEC13-T. Additional downstream sequence corresponding to 18 in-frame codons and a stop codon is highlighted in green. (D) SEC13 and SEC13-T amino acid sequences. SEC13 encodes a 322 AA protein with six WD-40 repeats (also known as WD or beta-transducin repeats) are underlined. Amino acid sequence of SEC13 which is different to SEC13T is shown in blue. SEC13-T may encode a 372 AA protein: Its first 285 amino acids are identical to SEC13 and the normal C-terminal 37 amino acids have been replaced by 87 amino acids (shown in red) encoded by exon 9b.