Liu S Y, Jiang H, Yuan B, Gao Y, Dai L S, Zhang J B
College of Animal Sciences, Jilin University, Changchun, Jilin, China.
College of Animal Sciences, Jilin University, Changchun, Jilin, China
Genet Mol Res. 2015 Jan 23;14(1):457-63. doi: 10.4238/2015.January.23.20.
Calpain-3 (CAPN3) is a member of the calpain family of Ca(2+)-regulated cysteine proteases, which play an important role in sarcomere remodeling and mitochondrial protein turnover, and thus, regulating beef tenderness in cattle. Currently, multiple CAPN3 transcripts have been detected in human, monkey, rat, and rabbit. However, whether this transcript is present in cattle remains unknown. In this study, we identified 2 CAPN3 transcripts in the skeletal muscle individuals of local black cattle from Jilin, China. One transcript corresponded to the known full-length protein and was referred to as CAPN3a, while the second transcript did not contain exons 2-19 and contained a single-nucleotide insert in the penultimate base of exon 1 compared to CAPN3a; this protein was referred to as CAPN3b. The expression level of CAPN3b was approximately 50-fold lower than that of CAPN3a. Moreover, CAPN3b mRNA was not translated into a functional protein because it had lost essential domains according to bioinformatic analysis. Our results not provide a foundation for understanding the function of CAPN3, but also are useful for further elucidating the effect of CAPN3 on meat quality in cattle.
钙蛋白酶-3（CAPN3）是Ca（2+）调节的半胱氨酸蛋白酶钙蛋白酶家族的成员，其在肌节重塑和线粒体蛋白质周转中起重要作用，从而调节牛的牛肉嫩度。目前，已在人、猴、大鼠和兔中检测到多种CAPN3转录本。然而，这种转录本是否存在于牛中仍不清楚。在本研究中，我们在中国吉林本地黄牛的骨骼肌个体中鉴定出2种CAPN3转录本。一种转录本对应于已知的全长蛋白，被称为CAPN3a，而第二种转录本不包含外显子2-19，并且与CAPN3a相比，在外显子1的倒数第二个碱基中含有一个单核苷酸插入；这种蛋白被称为CAPN3b。CAPN3b的表达水平比CAPN3a低约50倍。此外，根据生物信息学分析，CAPN3b mRNA未翻译成功能性蛋白，因为它失去了必需结构域。我们的结果不仅为理解CAPN3的功能提供了基础，而且对于进一步阐明CAPN3对牛肉品质的影响也很有用。
