Onizuka Naoko, Ito Yoshiaki, Inagawa Masayo, Nakahara Hiroyuki, Takada Shuji, Lotz Martin, Toyama Yoshiaki, Asahara Hiroshi
Department of Systems BioMedicine, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo, 157-0074, Japan,
J Orthop Sci. 2014 Jan;19(1):172-80. doi: 10.1007/s00776-013-0485-z. Epub 2013 Oct 29.
Mohawk (Mkx) is a homeodomain-containing transcription factor that is expressed in various mesoderm-derived tissues, particularly in developing tendons. In this study, we investigate the exact expression pattern and functions of Mkx in forelimbs.
We analyzed the forelimbs of Mkx knockout mice [from embryonic day (E) 18.5 to postnatal day (P) 28 weeks] by using knocked-in Venus signals, Masson trichrome staining, and hematoxylin and eosin (H&E) staining.
We detected Venus signals in forelimb tendons, pulleys, and volar plates (VPs) in P21 mice. In-depth histological analysis showed that compared to the wild-type mice, the Mkx knockout mice showed significant hypoplasia in the flexor digitorum profundus tendons from E18.5. The VPs and pulleys appeared normal until P0; however, by P14, they became increasingly thicker in Mkx-null mice compared to wild-type mice. The fiber alignment was particularly disrupted in VPs of Mkx-null mice.
These results suggest that Mkx is an important regulator of the differentiation of VPs and pulleys, as well as of tendon differentiation.
莫霍克（Mkx）是一种含同源结构域的转录因子，在各种中胚层衍生组织中表达，尤其是在发育中的肌腱中。在本研究中，我们调查了Mkx在前肢中的具体表达模式和功能。
我们通过使用敲入的维纳斯信号、马松三色染色和苏木精-伊红（H&E）染色，分析了Mkx基因敲除小鼠的前肢（从胚胎第18.5天到出生后第28周）。
我们在出生后21天小鼠的前肢肌腱、滑车和掌板（VP）中检测到维纳斯信号。深入的组织学分析表明，与野生型小鼠相比，Mkx基因敲除小鼠从胚胎第18.5天起，指深屈肌腱明显发育不全。掌板和滑车在出生后第0天看起来正常；然而，到出生后第14天，与野生型小鼠相比，Mkx基因敲除小鼠的掌板和滑车变得越来越厚。Mkx基因敲除小鼠掌板中的纤维排列尤其紊乱。
这些结果表明，Mkx是掌板和滑车分化以及肌腱分化的重要调节因子。
