Analysis of gene expression in the bovine corpus luteum through generation and characterisation of 960 ESTs

• Published in: Biochimica et biophysica acta Vol. 1679; no. 1; pp. 10 - 17
• Main Authors: Casey, Orla M., Fitzpatrick, Richard, McInerney, James O., Morris, Dermot G., Powell, Richard, Sreenan, Joseph M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 13.07.2004
• Subjects: Animals; Bioinformatics; Bos; Bovine ( Bos taurus); Cattle; Corpus luteum; Corpus Luteum - metabolism; DNA Probes; DNA, Complementary; Expressed sequence tag; Expressed Sequence Tags; Female; Gene Expression Profiling; Northern blot; Reverse Transcriptase Polymerase Chain Reaction; Corpus luteum; Northern blot; Expressed sequence tag; Bioinformatics; Bovine ( Bos taurus)
• ISSN: 0167-4781; 0006-3002; 1879-2634
• DOI: 10.1016/j.bbaexp.2004.03.011

To gain new insights into gene identity and gene expression in the bovine corpus luteum (CL) a directionally cloned CL cDNA library was constructed, screened with a total CL cDNA probe and clones representing abundant and rare mRNA transcripts isolated. The 5′-terminal DNA sequence of 960 cDNA clones, composed of 192 abundant and 768 rare mRNA transcripts was determined and clustered into 351 non-redundant expressed sequence tag (EST) groups. Bioinformatic analysis revealed that 309 (88%) of the ESTs showed significant homology to existing sequences in the protein and nucleotide public databases. Several previously unidentified bovine genes encoding proteins associated with key aspects of CL function including extracellular matrix remodelling, lipid metabolism/steroid biosynthesis and apoptosis, were identified. Forty-two (12%) of the ESTs showed homology with human or with other uncharacterised ESTs, some of these were abundantly expressed and may therefore play an important role in primary CL function. Tissue-specificity and temporal CL gene expression of selected clones previously unidentified in bovine CL tissue was also examined. The most interesting finds indicated that mRNA encoding squalene epoxidase was constitutively expressed in CL tissue throughout the oestrous cycle and 7-fold down-regulated ( P<0.05) in late luteal tissue, concomitant with the disappearance of systemic progesterone, suggesting that de novo cholesterol biosynthesis plays an important role in steroidogenesis. The mRNA encoding the growth factor, insulin-like growth factor-binding protein-related protein 1 (IGFBP-rP1), remained constant during the oestrous cycle and was 1.8-fold up-regulated ( P<0.05) in late luteal tissue implying a role in CL regression.