Lrrc75b, also known as AI646023, is a gene with an emerging role in biological regulation. It is involved in pathways related to myogenic differentiation and may also be associated with immunity-related pathways in the context of breast cancer [1,2]. Understanding its function is crucial as it can potentially provide insights into muscle-related development and breast cancer prognosis.

In a study on C2C12 myogenic differentiation, knockdown of Lrrc75b using siRNA in C2C12 myoblasts enhanced the expression of muscle-specific myogenin, increased myoblast fusion and myotube diameter. Conversely, adenovirus-mediated overexpression of Lrrc75b in C2C12 cells inhibited myoblast differentiation along with a decrease in myogenin expression. Also, the phosphorylation of extracellular signal-regulated kinase 1/2 (Erk1/2) was suppressed when Lrrc75b was silenced. This indicates that Lrrc75b is a negative regulator of C2C12 myogenic differentiation, modulating myogenin and Erk1/2 signaling [1]. Another study identified Lrrc75b as part of a prognostic signature composed of four protein-coding genes and one lncRNA, which could predict survival in breast cancer patients and was associated with lymph node metastasis status [2].

In conclusion, Lrrc75b acts as a negative regulator in C2C12 myogenic differentiation and is part of a signature that can predict breast cancer survival. Functional studies, potentially including gene knockout (KO) or conditional knockout (CKO) mouse models in future research, could further elucidate its role in muscle development and breast cancer, providing a better understanding of the underlying biological mechanisms and potential therapeutic targets for these disease-related areas. [1,2]

References:

1. Zhong, Yuechun, Zou, Liyi, Wang, Zonggui, Cui, Liao, Zuo, Changqing. 2016. Lrrc75b is a novel negative regulator of C2C12 myogenic differentiation. In International journal of molecular medicine, 38, 1411-1418. doi:10.3892/ijmm.2016.2738. https://pubmed.ncbi.nlm.nih.gov/27633041/

2. Sui, Yujie, Ju, Chunyan, Shao, Bin. 2019. A lymph node metastasis-related protein-coding genes combining with long noncoding RNA signature for breast cancer survival prediction. In Journal of cellular physiology, 234, 20036-20045. doi:10.1002/jcp.28600. https://pubmed.ncbi.nlm.nih.gov/30950057/