Newt lens transdifferentiation: from lentectomy to immuno-FISH.

Newt lens regeneration is achieved by a unique cellular regulation of transdifferentiation where the dorsal iris pigmented epithelial cells (PECs) dedifferentiate and redifferentiate into lens cells. Recent studies have shown that nuclear architecture of PECs is dynamically changed and unique epigenetic regulation in somatic nucleus is crucial in the lens transdifferentiation. Immuno-FISH, detection of protein and gene loci in nucleus, is one of the effective tools to analyze nuclear architecture of PECs.

Transcriptome analysis of newt lens regeneration reveals distinct gradients in gene expression patterns.

Regeneration of the lens in newts is quite a unique process. The lens is removed in its entirety and regeneration ensues from the pigment epithelial cells of the dorsal iris via transdifferentiation. The same type of cells from the ventral iris are not capable of regenerating a lens.

Salamander Hox clusters contain repetitive DNA and expanded non-coding regions: a typical Hox structure for non-mammalian tetrapod vertebrates?

Hox genes encode transcription factors that regulate embryonic and post-embryonic developmental processes. The expression of Hox genes is regulated in part by the tight, spatial arrangement of conserved coding and non-coding sequences. The potential for evolutionary changes in Hox cluster structure is thought to be low among vertebrates; however, recent studies of a few non-mammalian taxa suggest greater variation than originally thought.

A microarray analysis of gene expression patterns during early phases of newt lens regeneration.

Purpose: Notophthalmus viridescens, the red-spotted newt, possesses tremendous regenerative capabilities. Among the tissues and organs newts can regenerate, the lens is regenerated via transdifferentiation of the pigment epithelial cells of the dorsal iris, following complete removal (lentectomy). Under normal conditions, the same cells from the ventral iris are not capable of regenerating.

Lens regeneration in axolotl: new evidence of developmental plasticity.

Background: Among vertebrates lens regeneration is most pronounced in newts, which have the ability to regenerate the entire lens throughout their lives. Regeneration occurs from the dorsal iris by transdifferentiation of the pigment epithelial cells. Interestingly, the ventral iris never contributes to regeneration.

Epigenetics and regeneration.

During newt lens regeneration a unique transdifferentiation event occurs. In this process, dorsal iris pigmented epithelial cells transdifferentiate into lens cells. This system should provide a new insight into cellular plasticity in basic and applied research.

A complement receptor C5a antagonist regulates epithelial to mesenchymal transition and crystallin expression after lens cataract surgery in mice.

Purpose: To evaluate the effects of complement employing a mouse model for secondary cataract.

Methods: The role of complement receptor C5a (CD88) was evaluated after cataract surgery in mice. An antagonist specific to C5a receptor was administered intraperitoneally to mice.

Expressing exogenous genes in newts by transgenesis.

The great regenerative abilities of newts provide the impetus for studies at the molecular level. However, efficient methods for gene regulation have historically been quite limited. Here we describe a protocol for transgenically expressing exogenous genes in the newt Cynops pyrrhogaster.

Controlling gene loss of function in newts with emphasis on lens regeneration.

Here we describe a protocol for gene loss of function during regeneration in newts, specifically applied to lens regeneration. Knockdown with the use of morpholinos can be achieved both in vitro and in vivo, depending on the experimental design. These methods achieve desirable levels of gene knockdown, and thus can be compared with methods developed for use in other animals, such as zebrafish.

Changes in global histone modifications during dedifferentiation in newt lens regeneration.

Purpose: Reprogramming of pigmented epithelial cells (PECs) is a decisive process in newt lens regeneration. After lens removal PECs in dorsal iris dedifferentiate and revert to stem cell-like cells, and transdifferentiate into lens cells. Our purpose is to know how global histone modifications are regulated in the reprogramming of PECs.

miRNAs in newt lens regeneration: specific control of proliferation and evidence for miRNA networking.

Background: Lens regeneration in adult newts occurs via transdifferentiation of the pigment epithelial cells (PECs) of the dorsal iris. The same source of cells from the ventral iris is not able to undergo this process. In an attempt to understand this restriction we have studied in the past expression patterns of miRNAs.

Oocyte-type linker histone B4 is required for transdifferentiation of somatic cells in vivo.

The ability to reprogram in vivo a somatic cell after differentiation is quite limited. One of the most impressive examples of such a process is transdifferentiation of pigmented epithelial cells (PECs) to lens cells during lens regeneration in newts. However, very little is known of the molecular events that allow newt cells to transdifferentiate.

Expression profiles during dedifferentiation in newt lens regeneration revealed by expressed sequence tags.

Purpose: The adult newt can regenerate lens from pigmented epithelial cells (PECs) of the dorsal iris via dedifferentiation. The purpose of this research is to obtain sequence resources for a newt lens regeneration study and to obtain insights of dedifferentiation at the molecular level.

Methods: mRNA was purified from iris during dedifferentiation and its cDNA library was constructed.

Expression of stem cell pluripotency factors during regeneration in newts.

In this study, we present data indicating that mammalian stem cell pluripotency-inducing factors are expressed during lens and limb regeneration in newts. The apparent expression even in intact tissues and the ensued regulation during regeneration raises the possibility that these factors might regulate tissue-specific reprogramming and regeneration. Furthermore, these factors should enable us to understand the similarities and differences between animal regeneration in the newt and stem cell strategies in mammals.

Establishment of high-resolution FISH mapping system and its application for molecular cytogenetic characterization of chromosomes in newt, Cynops pyrrhogaster (Urodela, Amphibia).

Urodele amphibians (newts and salamanders) are important animal models for understanding regeneration mechanisms and genome evolution. We constructed ideograms of BrdU/dT- and C-banded karyotypes in the Japanese fire-belly newt, Cynops pyrrhogaster, which is useful as a model animal with extremely high ability of regeneration. We also established a high-resolution FISH mapping system for newts, and localized satellite DNA sequences, 18S rDNAs, telomeric (TTAGGG)n repeats and seven functional genes, including genes associated with lens regeneration, tyrosinase and two types of gamma crystallins, to chromosomes of the newt.

Rapid accumulation of nucleostemin in nucleolus during newt regeneration.

In newt regeneration, differentiated cells can revert to stem cell-like cells in which the proliferative ability and multipotentiality are restored after dedifferentiation. However, the molecular events that occur during the dedifferentiation still remain obscure. Nucleostemin has been identified in mammals as a nucleolar protein specific to stem cells and cancer cells.