title: Structural and molecular bases of rod photoreceptor morphogenesis and disease.
abstract: The rod cell has an extraordinarily specialized structure that allows it to carry out its unique function of detecting individual photons of light. Both the structural features of the rod and the metabolic processes required for highly amplified light detection seem to have rendered the rod especially sensitive to structural and metabolic defects, so that a large number of gene defects are primarily associated with rod cell death and give rise to blinding retinal dystrophies. The structures of the rod, especially those of the sensory cilium known as the outer segment, have been the subject of structural, biochemical, and genetic analysis for many years, but the molecular bases for rod morphogenesis and for cell death in rod dystrophies are still poorly understood. Recent developments in imaging technology, such as cryo-electron tomography and super-resolution fluorescence microscopy, in gene sequencing technology, and in gene editing technology are rapidly leading to new breakthroughs in our understanding of these questions. A summary is presented of our current understanding of selected aspects of these questions, highlighting areas of uncertainty and contention as well as recent discoveries that provide new insights. Examples of structural data from emerging imaging technologies are presented.
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA. Electronic address: twensel@bcm.edu.
authors.forename: Theodore G
authors.initials: TG
authors.lastname: Wensel
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Zhixian
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Ivan A
authors.initials: IA
authors.lastname: Anastassov
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Jared C
authors.initials: JC
authors.lastname: Gilliam
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: He
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Schmid
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Robichaux
mesh_terms: D020285:Cryoelectron Microscopy / Q000379:methods; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D009024:Morphogenesis; D012164:Retinal Diseases / Q000175:diagnosis* / Q000378:metabolism; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism* / Q000648:ultrastructure*
chemical_list: D008565:Membrane Proteins
keywords: Ciliopathies; Cryo-electron tomography; Disease mechanisms; Photoreceptor; Retinal degeneration; Retinal imaging