Abstract: Objective To explore the function of Fam171a1 gene by observing the phenotype changes of the
gene knockout rats. Methods Fam171a1 +/- genotype rats were made by CRISPR/ Cas9 targeting technology
and Fam171a1 -/- genotype rat was obtained by mating two Fam171a1 +/- genotype rats. Genotypes were
identified by DNA Analyzer 3730XL sequencing technology. The biological function of Fam171a1 gene was
explored by basic information retrieval. The expression of Fam171a1 protein in liver, brain and other major
organs of WT and Fam171a1 -/-  rats were detected by Western blot technique. The weight of 20 days old filial
rats was recorded and the serum biochemical indexes were detected by automatic biochemical analyzer.
Results Stable genetic Fam171a1 -/- genotype rats were obtained. Total of 125 Fam171a1 +/- rats were produced,
including 25 Fam171a1 -/- rats, 71 Fam171a1 +/- rats and 29 WT rats. FAM171A1 protein expressed in liver
and other major organs especially lung, brain and pancreatic tissue, and did not express or weakly expressed

in kidney, thymus and small intestine, but did not express in tissue of Fam171a1 -/-  rat. The average weight of
Fam171a1 -/- child rats was significantly lower than that of WT rats (t = 3.211, P = 0.0017), and serum CHE,
TP, AST and HDL level of Fam171a1 -/- adult rats were higher (t = 4.18, P ＜ 0.001; t = 6.26, P ＜ 0.001; t =
2.73, P = 0.02; t = 2.36, P = 0.03). Fertility was comparable between Fam171a1 -/- and WT rats (t = 0.2132, P =
0.8330). Conclusions Fam171a1 gene knockout SD rat was successfully obtained, and Fam171a1 gene may be
involved in the growth and lipid metabolism of SD rats and maintaining liver function.