Galectin gene expression in the elongating bovine conceptus
Baldwin, H. L., L. F. Grose, and D. J. Mathew.  2019.  Journal of Dairy Science.

Pregnancy loss in cattle is greatest in the first 30 d of gestation. Near Day 15 of gestation, bovine conceptuses will elongate and express galectin-1 (LGALS1), an immunosuppressive glycan binding protein believed to be essential for implantation. It is unclear, however, if other members of the bovine galectin family, including LGALS3, LGALS4, LGALS7, LGALS8, LGALS9 and a galectin 13-like gene (LGALS13L), are also expressed by the elongating conceptus. Therefore, galectin expression in elongating, Day 16, bovine conceptuses was examined by RT-qPCR. Considering galectins may also be expressed in other ruminant conceptuses, galectin expression was also measured in elongating ovine conceptuses. Angus heifer and Texel ewe uteri were collected 16 and 14 d after insemination, respectively, and flushed with PBS to collect elongating bovine (n = 4) and ovine (n = 3) conceptuses. The conceptuses were individually snap frozen and stored at −80°C until RT-qPCR. Bovine and ovine conceptus gene expression data were normalized to control genes GAPDH and YWHAZ. A general linear model (GLM) in SAS was used to test for dif- ferences between log-transformed relative expression data. The α-level was set at 0.05 and a Tukey’s test was included in the analysis. Data are presented as non-transformed means ± standard deviation of the mean. In bovine conceptuses, expression of LGALS3 (24.47 ± 6.41) and LGALS1 (21.80 ± 2.07) was similar yet greater than all other galectins measured (α = 0.05). Expression of LGALS8 (1.73 ± 0.27) was 12-fold less than LGALS1; however, LGALS8 expression was greater than LGALS9 (0.77 ± 0.77), LGALS13L (0.30 ± 0.10), LGALS4 (0.08 ± 0.01) and LGALS7 (0.02 ± 0.01) (α = 0.05). In sheep conceptuses, expression of LGALS3 (4.30 ± 0.78), LGALS1 (1.90 ± 0.25) and LGALS8 (1.68 ± 0.25) was similar. Other than LGALS9, which was undetectable, LGALS4 (0.20 ± 0.10) had the lowest level of expression of all galectins measured (α = 0.05). In conclusion, elongating bovine and ovine conceptuses express various members of the galectin gene family. The galectins may have important functions during early pregnancy in ruminants