Proliferative units in stratified squamous epithelium

Hume, W.J.; Potten, Christopher S

doi:10.1111/j.1365-2230.1983.tb01749.x

Cited by 25 publications

(22 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The similarities in expression and distribution of integrins between the skin and central cornea are interesting in that the cells within these epithelia differ markedly in their proliferative properties. In the skin, stem cells are located at the centers of distinct groupings of cells, termed epidermal proliferative units (30,31), which are located within the basal cell layer (32)(33)(34). In the cornea, the epithelial stem cell population is located in the basal cells of the limbus (35-38), an epithelial cell population found between the peripheral cornea and the conjunctiva.…”

Section: Discussionmentioning

confidence: 99%

Localized distribution of alpha 9 integrin in the cornea and changes in expression during corneal epithelial cell differentiation.

Stepp¹,

Zhu²,

Sheppard³

et al. 1995

J Histochem Cytochem.

View full text Add to dashboard Cite

A recently characterized integrin alpha-chain, alpha 9, forms heterodimers with the integrin beta 1-chain and is present in the skin with a distribution similar to that of alpha 2 and alpha 3, other beta 1 integrins. To determine whether alpha 9 is expressed in the stratified squamous epithelium of the cornea, we used immunohistochemical techniques to compare the distribution of alpha 9 in the adult mouse cornea with that of alpha 3. Abundant alpha 9 was expressed in the lateral and basal membranes of the basal cells of the conjunctiva and corneal limbus, but very little alpha 9 was present in the basal cells of the central corneal epithelium. In contrast, alpha 3 was present in the membranes of basal cells of the conjunctiva, limbus, and central cornea. To determine when during postnatal maturation of the corneal epithelium alpha 9 becomes restricted to the limbus, we looked at the distribution of alpha 9 and alpha 3 in the developing mouse eye from birth to eyelid opening. At birth, the basal cells of the cornea and developing limbal region did not express alpha 9, but there was abundant alpha 9 expressed in suprabasal cells between the fused lids and in the basal cells of the skin and conjunctiva. In contrast, alpha 3, integrin was expressed uniformly in the basal cells across the surface of the conjunctiva, limbus, and cornea and was present only in the basal cells of the epithelium between the fused eyelids. In the central cornea, alpha 9 expression increased in basal cells up until Day 10 after birth. After Day 10, alpha 9 expression in the central cornea began to decrease; after the lids were open, alpha 9 expression in the central cornea became restricted to the limbus. In the basal and suprabasal cells between the fused eyelids expression of alpha 9 became increasingly restricted over time to the basal cells. Recent data suggest that alpha 9 beta 1 can interact with tenascin. Our dual labeling confocal microscopy studies indicate that localization of alpha 9 and tenascin are not coordinated in the developing mouse cornea. Many recent studies have shown an important role for beta 1 integrins in mediating epithelial cell differentiation in vitro; in vivo, changes in integrin expression have been found in wound healing, psoriasis, and in basal and squamous cell carcinomas.(ABSTRACT TRUNCATED AT 400 WORDS)

show abstract

Section: Discussionmentioning

confidence: 99%

Localized distribution of alpha 9 integrin in the cornea and changes in expression during corneal epithelial cell differentiation.

Stepp¹,

Zhu²,

Sheppard³

et al. 1995

J Histochem Cytochem.

View full text Add to dashboard Cite

show abstract

“…3K). The filiform papillae of the tongue consist of two morphologically distinct compartments, an anterior, orthokeratinized epithelium and a posterior epithelium which gives rise to cornified spines (21,48). In sections of dorsal tongue epithelium, the 90-bp K5 promoter was expressed in the interpapillary suprabasal epithelium (thin arrow) and the anterior orthokeratinized epithelium of the filiform papilla (arrowheads).…”

Section: Resultsmentioning

confidence: 99%

Probing keratinocyte and differentiation specificity of the human K5 promoter in vitro and in transgenic mice.

Byrne¹,

Fuchs²

1993

Mol. Cell. Biol.

127

132

View full text Add to dashboard Cite

K5 and K14 are interesting in that they are broadly expressed in most stratified epithelial tissues (45). In these tissues, the pair is expressed in mitotically active basal keratinocytes, as judged by in situ hybridizations and/or immunohistochemical localization of epidermis (32, 42, 51), rodent forestomach (60), tongue (11), and various other stratified and pseudo-stratified epithelia (42). In addition, K5 has been detected histologically in a number of epithelial cells, including human thymic reticulum, the ORS, sebaceous glands, and both basal and myoepithelial cells of eccrine sweat glands and salivary glands (42). Indeed, an important and unifying feature of basal keratinocytes appears to be their unique ability to express K5 and K14, irrespective of body location (45). Given that cell-typespecific expression of KS and K14 genes appears to be at the transcriptional level (33, 69), the promoters of these genes * Corresponding author. seem to display an insensitivity to the varied environments of keratinocytes.Little is known about the molecular mechanisms which govern the complex expression of genes in the keratinocyte. Given that (i) K5 and K14 account for up to 30% of total protein of mitotically active keratinocytes and (ii) the tissuespecific expression of these proteins is regulated transcriptionally (33, 69), K5 and K14 genes provide ideal tools for investigating these regulatory mechanisms. The human KS and K14 genes have been cloned and sequenced (33,37). Cell type specificity of the KS promoter has been suggested from tissue culture studies (22,46), although the K14 promoter is promiscuously expressed in a number of cell types in vitro (30,75). While the in vivo behavior of the K5 promoter has not yet been explored, 2,100 bp of the K14 promoter is sufficient to direct expression of heterologous genes to the basal cells of stratified epithelia in transgenic mice (7,73,74).A number of recent studies have begun to focus on identifying putative regulatory domains and transcription factors that may be involved in expression of either endogenous or viral genes in keratinocytes (3,4,8,9,20,22,24,29,30,35,37,46,52,54,65,66,72,75). Thus far, only a few nuclear factors that both are restricted in their tissue specificity and appear to participate in conferring keratinocytespecific gene expression have been identified. One of these, AP2, has been implicated broadly in the regulation of endogenous and viral genes that are typically expressed in keratinocytes (29,30,40,54,65,66). However, AP2 does not appear to be sufficient for keratinocyte specificity on its own (29).The aim of this work was to explore the regulatory mechanisms involved in controlling keratinocyte-specific gene expression in culture and in transgenic animals. We 3176

show abstract

“…KSHV replication in keratinocytes and in vitro epithelium. In vivo epithelium arises from keratinocytes (progenitor cells) located in the basal layer (39). Similarly, in vitro organotypic raft cultures are formed from undifferentiated keratinocyte monolayers.…”

Section: Resultsmentioning

confidence: 99%

“…Three organotypic raft cultures (each derived from a separate donor in this study) were tested by PCR for the presence of herpes simplex virus types 1 and 2, varicella-zoster virus, cytomegalovirus, EBV, HHV-6, and high-risk HPV types (including types 6,11,16,18,31,33,35,39, and 45) and found to be negative. Reference testing was performed by the Molecular Diagnostic Laboratory and the HPV Laboratory at the University of Washington using previously published methodology (5,9,43,97).…”

Section: Methodsmentioning

confidence: 99%

“…Organotypic raft cultures accurately reproduce the process of epithelial differentiation in vitro, beginning with undifferentiated keratinocyte monolayers that become confluent and polarized, forming tight junctions prior to the initiation of keratinocyte differentiation. A proportion of the keratinocytes remain in the basal layer and maintain proliferative potential, while other cells leave the basal layer, lose mitotic capability, and differentiate into mature epithelial cells, forming the multilayered structure of the epithelium (39). Keratinocytes follow a programmed pattern of gene expression during differentiation, each step of which is characterized by the expression of keratin, and keratin-associated, proteins (59).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Activation of Kaposi's Sarcoma-Associated Herpesvirus Lytic Gene Expression during Epithelial Differentiation

Johnson¹,

Maronian

Vieira³

2005

J Virol

View full text Add to dashboard Cite

The oral cavity has been identified as the major site for the shedding of infectious Kaposi's sarcomaassociated herpesvirus (KSHV). While KSHV DNA is frequently detected in the saliva of KSHV seropositive persons, it does not appear to replicate in salivary glands. Some viruses employ the process of epithelial differentiation for productive viral replication. To test if KSHV utilizes the differentiation of oral epithelium as a mechanism for the activation of lytic replication and virus production, we developed an organotypic raft culture model of epithelium using keratinocytes from human tonsils. This system produced a nonkeratinized stratified squamous oral epithelium in vitro, as demonstrated by the presence of nucleated cells at the apical surface; the expression of involucrin and keratins 6, 13, 14, and 19; and the absence of keratin 1. The activation of KSHV lytic-gene expression was examined in this system using rKSHV.219, a recombinant virus that expresses the green fluorescent protein during latency from the cellular EF-1␣ promoter and the red fluorescent protein (RFP) during lytic replication from the viral early PAN promoter. Infection of keratinocytes with rKSHV.219 resulted in latent infection; however, when these keratinocytes differentiated into a multilayered epithelium, lytic cycle activation of rKSHV.219 occurred, as evidenced by RFP expression, the expression of the late virion protein open reading frame K8.1, and the production of infectious rKSHV.219 at the epithelial surface. These findings demonstrate that KSHV lytic activation occurs as keratinocytes differentiate into a mature epithelium, and it may be responsible for the presence of infectious KSHV in saliva.

show abstract

Proliferative units in stratified squamous epithelium

Cited by 25 publications

References 43 publications

Localized distribution of alpha 9 integrin in the cornea and changes in expression during corneal epithelial cell differentiation.

Localized distribution of alpha 9 integrin in the cornea and changes in expression during corneal epithelial cell differentiation.

Probing keratinocyte and differentiation specificity of the human K5 promoter in vitro and in transgenic mice.

Activation of Kaposi's Sarcoma-Associated Herpesvirus Lytic Gene Expression during Epithelial Differentiation

Contact Info

Product

Resources

About