Cloning and expression of circular transcript of mouse growth hormone receptor gene

Based on reports in the literature and search results on the circBase database, 8 circular transcripts of the mouse growth hormone receptor (GHR) gene were identified. In order to confirm the existence of the circular transcripts of the GHR gene (circGHRs) and to explore their expression patterns, the Kunming mouse (Mus musculus) was used as a research animal. This study detected the existence of circGHRs by RT-PCR amplification and sequencing, one of which was selected as circGHR for detailed analysis. The circular structure of circGHR was confirmed by RNase R treatment and reverse transcription. The spatiotemporal expression of circGHR and GHR mRNA was analyzed by qRT-PCR. The results showed that the full length of mouse circGHR was 820 nt, which was formed by circularization of exons 2-8 of the transcript of the GHR gene. RNase R tolerance analysis shows that mouse circGHR has the general characteristics of circular molecules and is not easily degraded by RNase R. Compared with oligo-d(T)18 primers, random primers have higher reverse transcription efficiency for circGHR, which further shows that circGHR is a poly(A)-free cyclic structure molecule. Tissue expression profile results show that circGHR is highly expressed in the liver and kidney of 1 week-old and 7-week old Kunming mice, but is low in pectoral muscles and leg muscles. The time-series expression profile of circGHR does not show any significant difference between the liver and pectoral muscle tissue. The circGHR expression in the leg muscle was low before 5 weeks of age but increased after 7 weeks of age. This study confirmed the existence of a circular transcript circGHR of the mouse GHR gene, and initially revealed the expression pattern of circGHR. The results of the study laid a foundation for in-depth developmental studies on the biological functions of the mouse circGHR and its mechanism of action regarding the growth and development of mice.