• AGTR1 belongs to GPCR. As angiotensin receptor I, AGTR1 is a component of renin angiotensin receptor (RAS). The RAS system mainly consists of AGTR1 and AGTR2 GPCRS, which are widely expressed in liver and kidney disease and are involved in diseases such as kidney disease, hypertension, diabetes and inflammation. AGTR1 has the potential to stimulate cell growth, migration or invasion and promote vascular growth, inflammation and immunity. Clinically, inhibition of AGTR1 by angiogenin antagonist ARB can inhibit angiogenesis and thus help to inhibit tumor growth. The blood vessels in the kidneys of the knockout mice were significantly thickened, showing renal inflammation, diabetes, and hypotension. At present, there are 45 drugs on the market, of which 7 are related to kidney disease, all of which are small molecule drugs.
• mRNA expression analysis: Rat Agtr1 mRNA was detectable in liver of wild-type SD rats. Human AGTR1 mRNA was detectable in liver of B-hAGTR1 rats. 
• Protein expression analysis: AGTR1 was detected in heart, liver and kidney of both wild-type rats and homozygous B-hAGTR1 rats , but weakly detected in colon, as anti-AGTR1 antibody was cross-reactive between human and rat.

Gene targeting strategy for B-hAGTR1 rats. The exon 3 of rats Agtr1a gene that encode extracellular domain, transmembrane domain and cytoplasmic portion is replaced by human counterparts in B-hAGTR1 rats. The genomic region of rat Agtr1a gene that encodes the promoter, 5’UTR and 3’UTR region of the rat gene are retained. The chimeric AGTR1 expression is driven by endogenous rat Agtr1a promoter, while rat Agtr1a gene transcription and translation will be disrupted. 

Strain specific analysis of AGTR1 mRNA expression in wild-type SD rats and B-hAGTR1 rats by RT-PCR. Liver RNA were isolated from wild-type SD rats (+/+) and homozygous B-hAGTR1 rats (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with rat or human AGTR1 primers. Rat Agtr1 mRNA was only detectable in wild-type rats. Human AGTR1 mRNA was exclusively detectable in homozygous B-hAGTR1 rats but not in wild-type rats. 

Western blot analysis of AGTR1 protein expression in homozygous B-hAGTR1 rats. Various tissue lysates were collected from wild-type SD rats (+/+) and homozygous B-hAGTR1 rats (H/H), and then analyzed by western blot with cross reactive anti-AGTR1 antibody (Abcam, ab124734). 40 μg total proteins were loaded for western blotting analysis. AGTR1 was detected in heart, liver and kidney of both wild-type rats and homozygous B-hAGTR1 rats, but weakly detected in colon.