(Q24337060)

GOA release 2020-03-11

keratin 15

1 reference

cytoskeleton organization

GOA release 2020-03-11

1 reference

GOA release 2020-03-11

author name string

R E Leube

1

0 references

B L Bader

2

0 references

F X Bosch

3

0 references

R Zimbelmann

4

0 references

T Achtstaetter

5

0 references

W W Franke

Structure and expression of the human haptoglobin locus

6

0 references

language of work or name

English

0 references

publication date

April 1988

0 references

published in

Journal of Cell Biology

0 references

volume

106

0 references

issue

4

0 references

page(s)

1249-61

0 references

cites work

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Complete sequence of a gene encoding a human type I keratin: sequences homologous to enhancer elements in the regulatory region of the gene

19 March 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Comparison of mouse and human keratin 18: a component of intermediate filaments expressed prior to implantation

19 March 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Amino acid sequence and gene organization of cytokeratin no. 19, an exceptional tail-less intermediate filament protein

19 March 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Sequence and expression of a human type II mesothelial keratin

19 March 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

57 Sequencing end-labeled DNA with base-specific chemical cleavages

19 March 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

The cDNA sequence of a Type II cytoskeletal keratin reveals constant and variable structural domains among keratins

19 March 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

The cDNA sequence of a human epidermal keratin: Divergence of sequence but conservation of structure among intermediate filament proteins

19 March 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

The catalog of human cytokeratins: patterns of expression in normal epithelia, tumors and cultured cells

19 March 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Cytokeratin expression in simple epithelia. III. Detection of mRNAs encoding human cytokeratins nos. 8 and 18 in normal and tumor cells by hybridization with cDNA sequences in vitro and in situ

19 March 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Human epidermal growth factor receptor cDNA sequence and aberrant expression of the amplified gene in A431 epidermoid carcinoma cells

19 March 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Immunocytochemical analysis of intermediate filaments in embryonic heart cells with monoclonal antibodies to desmin

7 April 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Differences in keratin synthesis between normal epithelial cells and squamous cell carcinomas are mediated by vitamin A

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Cell type-specific expression of bovine keratin genes as demonstrated by the use of complementary DNA clones.

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Protein complexes of intermediate-sized filaments: melting of cytokeratin complexes in urea reveals different polypeptide separation characteristics.

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Tissue Specificity of Epithelial Keratins: Differential Expression of mRNAs from Two Multigene Families

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

The mesothelial keratins: a new family of cytoskeletal proteins identified in cultured mesothelial cells and nonkeratinizing epithelia

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Immunolocalization of keratin polypeptides in human epidermis using monoclonal antibodies

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Keratin alterations during embryonic epidermal differentiation: a presage of adult epidermal maturation

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Two distinct classes of keratin genes and their evolutionary significance.

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Functional changes of intermediate filaments in fibroblastic cells revealed by a monoclonal antibody

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Synaptophysin: molecular organization and mRNA expression as determined from cloned cDNA.

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Amino acid sequences of mouse and human epidermal type II keratins of Mr 67,000 provide a systematic basis for the structural and functional diversity of the end domains of keratin intermediate filament subunits

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Classification of human epithelia and their neoplasms using monoclonal antibodies to keratins: strategies, applications, and limitations

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Retinoids as important regulators of terminal differentiation: examining keratin expression in individual epidermal cells at various stages of keratinization

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Three tightly linked genes encoding human type I keratins: conservation of sequence in the 5'-untranslated leader and 5'-upstream regions of coexpressed keratin genes

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Stage-specific keratins in Xenopus laevis embryos and tadpoles: the XK81 gene family

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Evidence for posttranscriptional regulation of the keratins expressed during hyperproliferation and malignant transformation in human epidermis

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Cloning of cDNA and amino acid sequence of a cytokeratin expressed in oocytes of Xenopus laevis

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

The role of keratin subfamilies and keratin pairs in the formation of human epidermal intermediate filaments

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Cytokeratin expression in simple epithelia. II. cDNA cloning and sequence characteristics of bovine cytokeratin A (no. 8).

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Cytokeratin expression in simple epithelia. I. Identification of mRNA coding for human cytokeratin no. 18 by a cDNA clone

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Nonepidermal members of the keratin multigene family: cDNA sequences and in situ localization of the mRNAs

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

The nature and significance of differential keratin gene expression

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Monoclonal antibody studies of mammalian epithelial keratins: a review.

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Patterns of expression and organization of cytokeratin intermediate filaments.

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Expression of the cytokeratin endo A gene during early mouse embryogenesis

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Amino acid sequence microheterogeneities of basic (type II) cytokeratins of Xenopus laevis epidermis and evolutionary conservativity of helical and non-helical domains

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Expression of epidermal keratins and filaggrin during human fetal skin development

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

The molecular biology of intermediate filaments

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Epidermal keratin gene expressed in embryos of Xenopus laevis

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

The sequence of a type II keratin gene expressed in human skin: conservation of structure among all intermediate filament genes

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Antibody to prekeratin. Decoration of tonofilament like arrays in various cells of epithelial character

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Immunofluorescent staining of keratin fibers in cultured cells

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Widespread occurrence of intermediate-sized filaments of the vimentin-type in cultured cells from diverse vertebrates

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Keratin cytoskeletons in epithelial cells of internal organs

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Identification and Characterization of Epithelial Cells in Mammalian Tissues by Immunofluorescence Microscopy Using Antibodies to Prekeratin

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Translational products of mRNAs coding for non-epidermal cytokeratins.

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Change of cytokeratin filament organization during the cell cycle: selective masking of an immunologic determinant in interphase PtK2 cells.

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Intermediate filament cytoskeleton of amnion epithelium and cultured amnion epithelial cells: expression of epidermal cytokeratins in cells of a simple epithelium

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Complete sequence of a bovine type I cytokeratin gene: conserved and variable intron positions in genes of polypeptides of the same cytokeratin subfamily

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Pair formation and promiscuity of cytokeratins: formation in vitro of heterotypic complexes and intermediate-sized filaments by homologous and heterologous recombinations of purified polypeptides.

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Identification of two types of keratin polypeptides within the acidic cytokeratin subfamily I.

27 September 2017

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Cytokeratins in normal lung and lung carcinomas. I. Adenocarcinomas, squamous cell carcinomas and cultured cell lines

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Sequential expression of mRNA-encoded keratin sets in neonatal mouse epidermis: Basal cells with properties of terminally differentiating cells

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Organization of a type I keratin gene. Evidence for evolution of intermediate filaments from a common ancestral gene

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Keratin expression in normal esophageal epithelium and squamous cell carcinoma of the esophagus

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Analysis of cytokeratin domains by cloning and expression of intact and deleted polypeptides in Escherichia coli

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Differentiation-related changes of cytokeratin expression in cultured keratinocytes and in fetal, newborn, and adult epidermis

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Differential localization of distinct keratin mRNA-species in mouse tongue epithelium by in situ hybridization with specific cDNA probes

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Human oesophageal submucosal glands. Their detection mucin, enzyme and secretory protein content

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Monoclonal antibodies to various acidic (type I) cytokeratins of stratified epithelia. Selective markers for stratification and squamous cell carcinomas.

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Monoclonal antibody analysis of bovine epithelial keratins. Specific pairs as defined by coexpression

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Different patterns of cytokeratin expression in the normal epithelia of the upper respiratory tract

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Growth and differentiation of human esophageal carcinoma cell lines

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Cytokeratins of normal epithelia and some neoplasms of the female genital tract

30 May 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Complete amino acid sequence of a mouse epidermal keratin subunit and implications for the structure of intermediate filaments

29 November 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Transient change of organization of vimentin filaments during mitosis as demonstrated by a monoclonal antibody

29 November 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Amino acid sequence diversity between bovine epidermal cytokeratin polypeptides of the basic (type II) subfamily as determined from cDNA clones

29 November 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Cytokeratin polypeptide patterns of different epithelia of the human male urogenital tract: immunofluorescence and gel electrophoretic studies

29 November 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Cell type heterogeneity of cytokeratin expression in complex epithelia and carcinomas as demonstrated by monoclonal antibodies specific for cytokeratins nos. 4 and 13.

29 November 2018

1 reference

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pmc&linkname=pmc_refs_pubmed&retmode=json&id=2114990

Homology of a conserved sequence in the tail domain of intermediate filament proteins with the loop region of calcium binding proteins

29 November 2018

1 reference

12 December 2020

Changes in keratin gene expression during terminal differentiation of the keratinocyte

1 reference

12 December 2020

Intrinsic and extrinsic regulation of the differentiation of skin, corneal and esophageal epithelial cells

1 reference

12 December 2020

Formation of Cytoskeletal Elements During Mouse Embryogenesis

1 reference

12 December 2020

Reactivity of monoclonal antibodies against intermediate filament proteins during embryonic development

1 reference

12 December 2020

Formation of Cytoskeletal Elements During Mouse Embryogenesis

1 reference

12 December 2020

Diversity of cytokeratins

1 reference

12 December 2020

The transfection of epidermal keratin genes into fibroblasts and simple epithelial cells: evidence for inducing a type I keratin by a type II gene

1 reference

12 December 2020

Changes in the Pattern of Cytokeratin Polypeptides in Epidermis and Hair Follicles During Skin Development in Human Fetuses

1 reference

12 December 2020

De novo synthesis and specific assembly of keratin filaments in nonepithelial cells after microinjection of mRNA for epidermal keratin

1 reference

12 December 2020

Complex Cytokeratin Polypeptide Patterns Observed in Certain Human Carcinomas

1 reference

12 December 2020

Tissue-specific expression of keratin proteins in human esophageal and epidermal epithelium and their cultured keratinocytes

1 reference

12 December 2020

Intermediate filament protein synthesis in preimplantation murine embryos

1 reference

12 December 2020

Aberrant expression of keratin proteins and cross-linked envelopes in human esophageal carcinomas

1 reference

12 December 2020

Integration of different keratins into the same filament system after microinjection of mRNA for epidermal keratins into kidney epithelial cells

1 reference

12 December 2020

Variation and frequency of cytokeratin polypeptide patterns in human squamous non-keratinizing epithelium

1 reference

12 December 2020

Keratin antigens in differentiating skin

1 reference

12 December 2020

Intermediate filament proteins as distinguishing markers of cell type and differentiated state in cultured human urinary tract epithelia

1 reference

12 December 2020

Cytokeratin patterns of human oral epithelia: Differences in cytokeratin synthesis in gingival epithelium and the adjacent alveolar mucosa

1 reference

12 December 2020