The domestic cattle (Bos taurus) has been a good animal model for embryo biotechnologies, such as in vitro fertilization and nuclear transfer. However, animals produced from these technologies often suffer from large-calf syndrome, suggesting fetal growth disregulation. The product of the insulin-like growth factor 2 (IGF2) gene is one of the most important fetal mitogens known to date. A detailed analysis of age-, tissue-, and allele-specific expression of IGF2 has not been performed in the bovine mainly because the majority of the bovine sequence has been unavailable. In the present study, we obtained virtually the entire sequence of the bovine IGF2 cDNA, identified expressed single-nucleotide polymorphisms (SNPs) in both exons 3 and 10, and determined the age-, tissue-, and promoter-specific expression of bovine IGF2 in fetal, calf, and adult tissues. We found that, similar to the human and mouse, bovine IGF2 is subjected to extensive transcriptional regulation through multiple promoters, alternative splicing and polyadenylation, as well as genetic imprinting. However, major differences were found in the regulation of the bovine IGF2 in nearly all aspects of age-, tissue-, promoter-, and allele-specific expression of IGF2, and the promoter-specific loss of imprinting from every other species studied, including cattle's close relatives, the sheep and the pig. The data presented here are of important reference value to cattle produced from embryo biotechnologies.

The genes insulin-like growth factor 2 (IGF2) and H19 express paternally and maternally, respectively, in humans, mice, sheep, and cattle. Additionally, IGF2 has been shown to be regulated by at least four promoters in a tissue- or development-specific manner. In the domestic pigs, the promoter- and tissue-specific imprinting pattern of IGF2 has not been well characterized, nor is the imprinting pattern of H19. In the present study, we identified two polymorphisms in each of IGF2 (exons 2 and 9) and H19 (exons 1 and 5) and determined the imprinting status of these two genes in 13 organs / tissues of week-old pigs. IGF2 P1 transcript is bi-allelically expressed (not imprinted) in all major organs studied, while the majority of IGF2 transcripts are expressed from promoters 2-4 and are imprinted. H19 is exclusively expressed from the maternal allele in all major organs, concurrent with observations in other species.

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Fatty acid transport protein 1 (FATP-1) is a membrane associated protein, which facilitates the long chain fatty acids (LCFA) transport across the plasma membrane for the LCFA utilization and storage. In this study, the cDNA structure of porcine FATP-1 was investigated and the gene expression patterns of porcine FATP-1 in different tissues were tested by RT-PCR and Southern blot analysis. The results showed that there were five pFATP-1 mRNA species, namely, FATP-1a, FATP-1aV, FATP-1b, FATP-1c and FATP-1cV and are generated by alternative splicing of primary transcript. Deduced pFATP-1a protein showed 91.6% and 87.5% identities with those of human and rat. RT-PCR and Southern blot analysis demonstrated widespread tissue distribution of each pFATP-1 isoform mRNA, most abundantly in the brain, heart, lung, jejunum, testis, pancreas and trapezius muscle. Real-time quantitative RT-PCR revealed that pFATP-1 mRNA expressions in masseter and trapezius muscles were much higher than those in longissimus, gluteus medius and adipose tissues. These results suggested a crucial physiological role of pFATP-1 in fatty acid utilization in muscles, especially red muscles tissues, rather than fat storage in adipose tissues.