Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia.
Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Kazan University, Kazan, Republic of Tatarstan, Russia.
Bull Exp Biol Med. 2024 Oct;177(6):731-735. doi: 10.1007/s10517-024-06259-w. Epub 2024 Oct 23.
Using produced polyclonal antibodies specific to the N-terminal sequence (residues 61-298) of rat obscurin, we investigated the isoform composition of this protein in 4 striated muscles: myocardium of the left ventricle, diaphragm, skeletal m. gastrocnemius (containing mainly fast fibers), and m. soleus (containing mainly slow fibers). The m. gastrocnemius, m. soleus, and diaphragm were found to have 2 giant isoforms of obscurin: a smaller A-isoform and a larger B-isoform. Their molecular weights were ~870 and ~1150 kDa in the diaphragm and m. gastrocnemius and ~880 and ~1130 kDa in m. soleus, respectively. The B-isoform to A-isoform ratio was 1:3 in the diaphragm and m. soleus and 1:4 in the m. gastrocnemius. In the left-ventricular myocardium, A-isoform of obscurin with a molecular weight of ~880 kDa was found. No other obscurin isoforms or their fragments within the molecular weight range of 10 up to ~800 kDa were revealed in the investigated rat striated muscles. The antibodies produced are recommended for research into qualitative and quantitative changes of giant obscurin isoforms in rat striated muscles in the norm and during the development of pathological processes.
我们利用针对大鼠 obscurin N 端序列（残基 61-298）的多克隆抗体，研究了该蛋白在 4 种横纹肌中的同工型组成：左心室心肌、横膈膜、骨骼肌腓肠肌（主要含快速纤维）和比目鱼肌（主要含慢速纤维）。我们发现腓肠肌、比目鱼肌和横膈膜含有 2 种 obscurin 巨同工型：较小的 A-同工型和较大的 B-同工型。它们在横膈膜和腓肠肌中的分子量约为 870 和 1150 kDa，在比目鱼肌中的分子量约为 880 和 1130 kDa。B-同工型与 A-同工型的比例在横膈膜和比目鱼肌中为 1:3，在腓肠肌中为 1:4。在左心室心肌中，发现分子量约为 880 kDa 的 obscurin A-同工型。在所研究的大鼠横纹肌中，没有发现分子量在 10 到 800 kDa 范围内的其他 obscurin 同工型或其片段。所产生的抗体推荐用于研究大鼠横纹肌中 giant obscurin 同工型在正常和病理过程发展过程中的定性和定量变化。
