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

Abstract:
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