La Antigen [SS/B] | ScienceGate

Langerhans cells of mammalian stratified squamous epithelial have proven to be an enigma since their discovery in 1868. These dendritic suprabasal cells have been considered as related to melanocytes either as effete cells, or as post divisional products. Although grafting experiments seemed to demonstrate the independence of the cell types, much confusion still exists. The presence in the epidermis of a cell type with morphological features seemingly shared by melanocytes and Langerhans cells has been especially troublesome. This so called "indeterminate", or " -dendritic cell" lacks both Langerhans cells granules and melanosomes, yet it is clearly not a keratinocyte. Suggestions have been made that it is related to either Langerhans cells or melanocyte. Recent studies have unequivocally demonstrated that Langerhans cells are independent cells with immune function. They display Fc and C3 receptors on their surface as well as la (immune region associated) antigens.

Download Full-text

Characterization and purification of lupus antigen La, and RNA-binding protein

Molecular and Cellular Biology ◽

10.1128/mcb.5.3.586-590.1985 ◽

1985 ◽

Vol 5 (3) ◽

pp. 586-590

Author(s):

A M Francoeur ◽

E K Chan ◽

J I Garrels ◽

M B Mathews

Keyword(s):

Hela Cell ◽

Gel Electrophoresis ◽

Rna Binding ◽

Binding Protein ◽

Rna Binding Protein ◽

In Vitro Translation ◽

Cell Protein ◽

Two Dimensional Gel Electrophoresis ◽

La Antigen

HeLa cell La antigen, an RNA-binding protein, was characterized by using two-dimensional gel electrophoresis. Eight isoelectric forms (pI 6 to 7) were observed, many containing phosphate. An in vitro translation product similar in size and antigenicity was identified. The HeLa cell protein purified by using an assay based on ribonucleoprotein reconstitution with adenovirus VA RNAI also comprised several isoelectric forms.

Download Full-text

La antigen recognizes and binds to the 3'-oligouridylate tail of a small RNA.

Molecular and Cellular Biology ◽

10.1128/mcb.4.6.1134 ◽

1984 ◽

Vol 4 (6) ◽

pp. 1134-1140 ◽

Cited By ~ 56

Author(s):

M B Mathews ◽

A M Francoeur

Keyword(s):

Rna Polymerase ◽

Small Rna ◽

Rna Polymerase Iii ◽

Cellular Protein ◽

Cross Linking ◽

Antigen Binding ◽

Polymerase Iii ◽

La Antigen ◽

Covalently Linked

The La antigen is a cellular protein which interacts with many RNA species that are products of RNA polymerase III, including the adenovirus virus-associated (VA) RNAs. We demonstrate that the efficiency of antigen binding in vitro is determined by the number of U residues at the RNA 3' terminus. Forms of VA RNAI with more than two terminal U residues are fully bound, forms with two U residues are partially bound, and forms with fewer than two U residues are not bound at all. The antigen can be covalently linked to VA RNA by UV irradiation, and the site of cross-linking is shown to contain the 3' terminus of the RNA. We conclude that the antigen recognizes the U-rich 3' tail of VA RNA, and presumably that of other polymerase III products, and that it binds at or close to this site.

Download Full-text

La antigen recognizes and binds to the 3'-oligouridylate tail of a small RNA

Molecular and Cellular Biology ◽

10.1128/mcb.4.6.1134-1140.1984 ◽

1984 ◽

Vol 4 (6) ◽

pp. 1134-1140

Author(s):

M B Mathews ◽

A M Francoeur

Keyword(s):

Rna Polymerase ◽

Small Rna ◽

Rna Polymerase Iii ◽

Cellular Protein ◽

Cross Linking ◽

Antigen Binding ◽

Polymerase Iii ◽

La Antigen ◽

Covalently Linked

The La antigen is a cellular protein which interacts with many RNA species that are products of RNA polymerase III, including the adenovirus virus-associated (VA) RNAs. We demonstrate that the efficiency of antigen binding in vitro is determined by the number of U residues at the RNA 3' terminus. Forms of VA RNAI with more than two terminal U residues are fully bound, forms with two U residues are partially bound, and forms with fewer than two U residues are not bound at all. The antigen can be covalently linked to VA RNA by UV irradiation, and the site of cross-linking is shown to contain the 3' terminus of the RNA. We conclude that the antigen recognizes the U-rich 3' tail of VA RNA, and presumably that of other polymerase III products, and that it binds at or close to this site.

Download Full-text