Spatial, temporal, and hormonal regulation of epidermal keratin expression during development of the frog, Xenopus laevis

Nishikawa, Akio; Shimizu‐Nishikawa, Keiko; Miller, Leon K.

doi:10.1016/0012-1606(92)90222-3

Cited by 58 publications

(31 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Two types of antibodies were generated against the 63-kDa keratin to study its expression pattern. One type of the two strongly reacted with spinous and granular cells, and weakly with adult basal cells (Nishikawa et al, 1992). The other type strongly recognized adult epidermal basal cells (Kinoshita and Sasaki, 1994a).…”

Section: Introductionmentioning

confidence: 93%

Metamorphosis‐dependent transcriptional regulation of xak‐c, a novel Xenopus type I keratin gene

Watanabe

Tanaka

Kobayashi

et al. 2002

Developmental Dynamics

View full text Add to dashboard Cite

Anuran larvae transform their epidermis to the adult counterpart during metamorphosis. The major event of this process is the proliferation of larval epidermal basal cells and their differentiation into adult ones. The present study isolated novel type I keratin cDNA dubbed xak-c (Xenopus adult keratin-c) that was exclusively expressed in adult epidermal basal cells. The gene started its expression in the larval epidermis at the onset of metamorphosis. Thyroid hormone (TH) induced the precocious expression of the gene in the epidermis of premetamorphic tadpoles. To study the transcriptional regulation of this gene in relation to epidermal metamorphosis, a 2.8 kb 5 -flanking region of xak-c was cloned and its promoter activity was investigated. Gene constructs were made so as to contain the xak-c promoter region and gene of EGFP or luciferase as a reporter gene and were transfected into various types of cells, which revealed that the 5 -flanking region had an epidermal cellspecific transcriptional activity in both anurans and mammals. Larval skin tissues of Xenopus were transfected with the constructs and cultured in the presence and absence of TH, which showed that the promoter region is responsive to TH, although the region did not contain the consensus TH response element-like sequence. In sharp contrast, the promoter region did not respond to TH in the adult skin, clearly indicating that the cloned region contains specific sequences that respond to metamorphosis-dependent transcription factor(s).

show abstract

Section: Introductionmentioning

confidence: 93%

Metamorphosis‐dependent transcriptional regulation of xak‐c, a novel Xenopus type I keratin gene

Watanabe

Tanaka

Kobayashi

et al. 2002

Developmental Dynamics

View full text Add to dashboard Cite

show abstract

“…Larval-to-adult conversion of organs during amphibian metamorphosis is caused by such cell replacement and thus provides an ideal model for clarifying the mechanisms of programmed cell death of larvaltype cells and proliferation of adult-type cells (IshizuyaOka andShimozawa 1991, 1992;Miller 1996;Hayashi 1994, 1995;Nishikawa et al 1989Nishikawa et al , 1992Yoshizato 1989). All metamorphic events are triggered by T 3 and T 4 , and modulated by corticoids, and thus amphibian metamorphosis should prove useful for studying hormone-induced programmed cell death during developmentally regulated cell replacement.…”

Section: Introductionmentioning

confidence: 99%

T 3 -hydrocortisone synergism on adult-type erythroblast proliferation and T 3 -mediated apoptosis of larval-type erythroblasts during erythropoietic conversion in Xenopus laevis

Nishikawa

Hayashi

1999

Histochemistry and Cell Biology

View full text Add to dashboard Cite

The conversion of an erythropoietic system from larval to adult type in anuran amphibia may possibly come about through cell replacement. The hormonal regulation of apoptosis of larval-type precursor cells and adult-type cell proliferation has yet to be examined in detail. In amphibians, corticoids synergize T3 action during metamorphosis. In the present study, examination was made of the process of larval-to-adult conversion in the liver erythropoietic site of Xenopus laevis, with special attention to how these metamorphic hormones, T3 and corticoid, regulate programmed cell death specific for larval erythroblasts and the proliferation of adult cells. Immunohistochemical analysis of liver sections indicates that the number of larval erythroblasts decreased to less than 50% at the early climax stage (stages 59-60) of metamorphosis. Overall liver morphology greatly changed subsequent to the climax stage from the three-lobe to the two-lobe shape. The addition of T3 (10(-8) M) to premetamorphic tadpoles induced considerable liver morphological change and a 50% decrease in larval-type erythroblasts. These erythroblast decreases seem to take place through the apoptotic process, since double-staining experiments with in situ DNA nick-end labeling (TUNEL) and hemoglobin immunostaining revealed that DNA breakage of nuclei, a well-known feature of apoptosis, occurred specifically in larval erythroblasts during prometamorphosis. Hydrocortisone (HC), which modulates T3 action during metamorphosis, was found not to be a factor in larval cell decrease. But adult erythroblasts increased by 8 times as much through the action of T3 and 32 times as much by the action of T3 plus HC, indicating the important action of T3-HC synergism. It thus follows that the erythropoietic system is converted during metamorphosis effectively by two distinct hormonal mechanisms, T3-HC synergism on adult erythroblast proliferation and T3-mediated programmed death of larval precursor cells.

show abstract

“…Biochemical and immunocytochemical studies have shown that keratinization in actinopterygian fish involves the synthesis of several keratins with a narrower range of molecular weight (42-58 kDa) than in amphibians (47-66 kDa, rarely a 69 kDa form; Reeves, 1975;Ellison et al, 1985;Nishikawa et al, 1992) and amniotes (40 -68 kDa; rarely a 77-78 kDa form; Sun et al, 1983;Moll et al, 1982;Fuchs and Marchuk, 1983;0'Guin et al, 1987;Carver and Sawyer, 1987;Shames et al, 1989;Alibardi et al, 2000. Most actinopterygian fish keratins are acidic or neutral while true basic keratins are absent (Markl and Franke, 1988;Markl et al, 1989;Alarcon et al, 1994;Zaccone et al, 1995;Groff et al, 1997;Conrad et al, 1998).…”

mentioning

confidence: 98%

Keratinization of the epidermis of the Australian lungfish Neoceratodus forsteri (dipnoi)

Alibardi

Joss

2003

Journal of Morphology

View full text Add to dashboard Cite

The differentiation of the epidermis in sarcopterigian fish may reveal some trend of keratinization followed by amphibian ancestors to adapt their epidermis to land. Therefore, the process of keratinization of the epidermis of the Australian lungfish Neoceratodus forsteri was studied by histochemistry, electron microscopy, and keratin immunocytochemistry. The epidermis is tri-stratified in a 2-3-month-old tadpole but becomes 6-8 stratified in young adults. Keratin filaments increase from basal to external cells where loose tonofilament bundles are present. This is shown also by the comparison of positivity to sulfhydryl groups and increasing immunoreactivity to alpha-keratins in more external layers of the epidermis. Two broad-spectrum anti alpha-keratin monoclonal antibodies (AE1 and AE3) stain all epidermal layers as they do in actinopterigian fish. In the adult epidermis, but not in that of the larva, the AE2 antibody (a marker of keratinization in mammalian epidermis) often immunolabels more heavily the external keratinized layers where sulfhydryl groups are more abundant. Mucous granules are numerous and concentrate on the external surface of the epidermis to be discharged and contribute to cuticle formation. Keratin is therefore embedded in a mucus matrix, but neither compact keratin masses nor cell corneous envelope were seen in external cells. It is not known whether specific matrix proteins are associated with mucus. There was no immunolocalization of the keratin-associated proteins, filaggrin and loricrin, which suggests that the epidermis of this species lacks the matrix and cell corneus envelope proteins characteristic of that of amniotes. In conclusion, while specific keratins (AE2 positive) are probably produced in the uppermost layers as in amphibian epidermis, no interkeratin, matrix proteins seem to be present in external keratinocytes of the lungfish other than mucus.

show abstract

Spatial, temporal, and hormonal regulation of epidermal keratin expression during development of the frog, Xenopus laevis

Cited by 58 publications

References 22 publications

Metamorphosis‐dependent transcriptional regulation of xak‐c, a novel Xenopus type I keratin gene

Metamorphosis‐dependent transcriptional regulation of xak‐c, a novel Xenopus type I keratin gene

T 3 -hydrocortisone synergism on adult-type erythroblast proliferation and T 3 -mediated apoptosis of larval-type erythroblasts during erythropoietic conversion in Xenopus laevis

Keratinization of the epidermis of the Australian lungfish Neoceratodus forsteri (dipnoi)

Contact Info

Product

Resources

About