Cellular transparency in vivo: the search for possible mechanisms

Why one particular cell in vivo is transparent while another is not? Modern methods of in vivo optical imaging: in vivo optical recording of cellular activity, fluorescent probe cellular microchemistry, neuronal optostimulation, optogenetics, in vivo arteriosclerotic research: all these technologies would benefit from in vivo transparent tissue. Using optical and electron microscopy immunostaining methods we have found that αA-crystallin protein abundantly present in transparent cells of the vertebrates optical tract (crystal lens, cornea), is also present in other transparent cells from the retina (Müller cells, cones) from different vertebrate classes (birds, anurans, mammals). Abundancy of one particular substance in exclusively transparent cells in vertebrates suggest that αA-crystallins can be the cause of the cellular transparency: two possible physical mechanisms are discussed. This finding may help to develop the genetic approach to make cells transparent: the gene αA-crystallins are well known, for transgenes with αA-crystallins abundantly expressed in neurons and astrocytes may have a very transparent brain, animals with naturally transparent skin can be developed as well. Development of model animals with transparent tissue is only one of possible outcomes, this work may contribute do general knowledge on the genetics of biological transparency. This work has been supported by NIH SC2GM111149 Grant.