Differential expression of ISG 15 mRNA in peripheral blood mononuclear cells of nulliparous and multiparous pregnant versus non-pregnant Bos indicus cattle.

Embryonic mortality is found to be the main source of reproductive wastage in domestic ruminants. Many genes are involved in the growth and development of the embryo, and the interferon-stimulated gene 15 (ISG 15) is one of the major gene stimulated by interferon tau, the maternal recognition of pregnancy signal in ruminants. In this study, both genomic and cDNA sequences of ISG 15 from Bos indicus (Deoni breed) were amplified and characterized. The genomic sequence of Deoni ISG 15 exhibited 99% identity with Bos taurus and 97% identity with that of Bos mutus and Bubalus bubalis. Moreover qRT-PCR analysis revealed constitutive expression of the ISG 15 mRNA in peripheral blood mononuclear cells of Deoni heifers and multiparous cows during early pregnancy. Fourteen Deoni heifers and fifteen multiparous Deoni cows were synchronized for timed AI by CIDR-Ovsynch protocol, and six animals were kept as cyclic control in each group. Blood samples were collected on days 7, 14, 16, 18, 21, 30 and 45 from the day of AI. Pregnancy was confirmed by plasma progesterone level through ELISA. A significantly higher expression of ISG 15 mRNA was found on day 16 (p < .05) and day 18 (p < .05) of pregnancy in nulliparous heifers. Although in multiparous Deoni cows ISG 15 expression was greater in pregnant cows, difference was statistically non-significant. The result of this study indicates that ISG 15 gene expression is upregulated during 16-18 days of pregnancy and could be used as an early pregnancy marker in dairy cows especially in heifers.

Genes Regulating Maternal Recognition of Pregnancy in Domestic Animals: an Update

ABSTRACT Early embryonic mortality is one of the main sources of reproductive wastages and major constraints for full exploitation of the production potential of livestock. The survivality of embryo during early embryonic life is mostly dependent on the efficiency with which the maternal recognition of pregnancy (MRP) is established. Maternal recognition of pregnancy involves molecular dialogue between the trophoblast of conceptus and uterine endometrium. Embryonic development to the blastocyst stage and uterine differentiation to the receptive environment are crucial for successful establishment of the embryo-uterine cross-talk that leads to the initiation and progression of successful implantation. Unravelling the complex intricate molecular and cellular dialogues between the conceptus and uterine environment will facilitate development of strategies to augment early embryo survivality.