spacer gif spacer gif spacer gif spacer gif ARCHIVE ANNOUNCEMENT! spacer gif
 QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    


This Article
Right arrow Full Text (PDF)
Right arrow References
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Thomas, P. Q.
Right arrow Articles by Beddington, R. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Thomas, P. Q.
Right arrow Articles by Beddington, R. S.

Development, Vol 125, Issue 1 85-94, Copyright © 1998 by Company of Biologists


JOURNAL ARTICLES

Hex: a homeobox gene revealing peri-implantation asymmetry in the mouse embryo and an early transient marker of endothelial cell precursors

PQ Thomas, A Brown and RS Beddington
MRC National Institute for Medical Research, London, UK.

The divergent homeobox gene Hex exhibits three notable expression patterns during early mouse development. Initially Hex is expressed in the primitive endoderm of the implanting blastocyst but by 5.5 dpc its transcripts are present only in a small patch of visceral endoderm at the distal tip of the egg cylinder. Lineage analysis shows that these cells move unilaterally to assume an anterior position while continuing to express Hex. The primitive streak forms on the opposite side of the egg cylinder from this anterior Hex expression domain approximately 24 hours after the initial anterior movement of the distal visceral endoderm. Thus, Hex expression marks the earliest unequivocal molecular anteroposterior asymmetry in the mouse embryo and indicates that the anteroposterior axis of the embryo develops from conversion of a proximodistal asymmetry established in the primitive endoderm lineage. Subsequently, Hex is expressed in the earliest definitive endoderm to emerge from the streak and its expression within the gut strongly suggests that the ventral foregut is derived from the most anterior definitive endoderm and that the liver is probably the most anterior gut derivative. Hex is also an early marker of the thyroid primordium. Within the mesoderm, Hex is transiently expressed in the nascent blood islands of the visceral yolk sac and later in embryonic angioblasts and endocardium. Comparison with flk-1 (T. P. Yamaguchi et al., Development 118, 489-498, 1993) expression indicates that Hex is also an early marker of endothelial precursors but its expression in this progenitor population is much more transient than that of flk-1, being downregulated once endothelial cell differentiation commences.


This article has been cited by other articles:


Home page
Physiol. Rev.Home page
G. R. van den Brink
Hedgehog Signaling in Development and Homeostasis of the Gastrointestinal Tract
Physiol Rev, October 1, 2007; 87(4): 1343 - 1375.
[Abstract] [Full Text] [PDF]


Home page
Mol. Biol. CellHome page
S. Wanderling, B. B. Simen, O. Ostrovsky, N. T. Ahmed, S. M. Vogen, T. Gidalevitz, and Y. Argon
GRP94 Is Essential for Mesoderm Induction and Muscle Development Because It Regulates Insulin-like Growth Factor Secretion
Mol. Biol. Cell, October 1, 2007; 18(10): 3764 - 3775.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
V. A. McLin, S. A. Rankin, and A. M. Zorn
Repression of Wnt/{beta}-catenin signaling in the anterior endoderm is essential for liver and pancreas development
Development, June 15, 2007; 134(12): 2207 - 2217.
[Abstract] [Full Text] [PDF]


Home page
Eur J EndocrinolHome page
E. Al Taji, H. Biebermann, Z. Limanova, O. Hnikova, J. Zikmund, C. Dame, A. Gruters, J. Lebl, and H. Krude
Screening for mutations in transcription factors in a Czech cohort of 170 patients with congenital and early-onset hypothyroidism: identification of a novel PAX8 mutation in dominantly inherited early-onset non-autoimmune hypothyroidism
Eur. J. Endocrinol., May 1, 2007; 156(5): 521 - 529.
[Abstract] [Full Text] [PDF]


Home page
ScienceHome page
K. Hayashi, S. M. C. de Sousa Lopes, and M. A. Surani
Germ Cell Specification in Mice
Science, April 20, 2007; 316(5823): 394 - 396.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
C. L. Andoniadou, M. Signore, E. Sajedi, C. Gaston-Massuet, D. Kelberman, A. J. Burns, N. Itasaki, M. Dattani, and J. P. Martinez-Barbera
Lack of the murine homeobox gene Hesx1 leads to a posterior transformation of the anterior forebrain
Development, April 15, 2007; 134(8): 1499 - 1508.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
M. M. Shen
Nodal signaling: developmental roles and regulation
Development, March 15, 2007; 134(6): 1023 - 1034.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
A. L. Zamparini, T. Watts, C. E. Gardner, S. R. Tomlinson, G. I. Johnston, and J. M. Brickman
Hex acts with {beta}-catenin to regulate anteroposterior patterning via a Groucho-related co-repressor and Nodal
Development, September 15, 2006; 133(18): 3709 - 3722.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
C. Chazaud and J. Rossant
Disruption of early proximodistal patterning and AVE formation in Apc mutants
Development, September 1, 2006; 133(17): 3379 - 3387.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
A. S. Rakeman and K. V. Anderson
Axis specification and morphogenesis in the mouse embryo require Nap1, a regulator of WAVE-mediated actin branching
Development, August 15, 2006; 133(16): 3075 - 3083.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
D. Mesnard, M. Guzman-Ayala, and D. B. Constam
Nodal specifies embryonic visceral endoderm and sustains pluripotent cells in the epiblast before overt axial patterning
Development, July 1, 2006; 133(13): 2497 - 2505.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
A. Jouneau, Q. Zhou, A. Camus, V. Brochard, L. Maulny, J. Collignon, and J.-P. Renard
Developmental abnormalities of NT mouse embryos appear early after implantation.
Development, April 1, 2006; 133(8): 1597 - 1607.
[Abstract] [Full Text] [PDF]


Home page
Nucleic Acids ResHome page
K. Kurimoto, Y. Yabuta, Y. Ohinata, Y. Ono, K. D. Uno, R. G. Yamada, H. R. Ueda, and M. Saitou
An improved single-cell cDNA amplification method for efficient high-density oligonucleotide microarray analysis
Nucleic Acids Res., March 17, 2006; 34(5): e42 - e42.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
C. Chen, S. M. Ware, A. Sato, D. E. Houston-Hawkins, R. Habas, M. M. Matzuk, M. M. Shen, and C. W. Brown
The Vg1-related protein Gdf3 acts in a Nodal signaling pathway in the pre-gastrulation mouse embryo
Development, January 15, 2006; 133(2): 319 - 329.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
J. Chu, J. Ding, K. Jeays-Ward, S. M. Price, M. Placzek, and M. M. Shen
Non-cell-autonomous role for Cripto in axial midline formation during vertebrate embryogenesis
Development, December 15, 2005; 132(24): 5539 - 5551.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
A. Kubo, V. Chen, M. Kennedy, E. Zahradka, G. Q. Daley, and G. Keller
The homeobox gene HEX regulates proliferation and differentiation of hemangioblasts and endothelial cells during ES cell differentiation
Blood, June 15, 2005; 105(12): 4590 - 4597.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
T. A. Rodriguez, S. Srinivas, M. P. Clements, J. C. Smith, and R. S. P. Beddington
Induction and migration of the anterior visceral endoderm is regulated by the extra-embryonic ectoderm
Development, June 1, 2005; 132(11): 2513 - 2520.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
N. Nishioka, S. Nagano, R. Nakayama, H. Kiyonari, T. Ijiri, K. Taniguchi, W. Shawlot, Y. Hayashizaki, H. Westphal, R. R. Behringer, et al.
Ssdp1 regulates head morphogenesis of mouse embryos by activating the Lim1-Ldb1 complex
Development, June 1, 2005; 132(11): 2535 - 2546.
[Abstract] [Full Text] [PDF]


Home page
Mol. Cell. Biol.Home page
N. Gotoh, K. Manova, S. Tanaka, M. Murohashi, Y. Hadari, A. Lee, Y. Hamada, T. Hiroe, M. Ito, T. Kurihara, et al.
The Docking Protein FRS2{alpha} Is an Essential Component of Multiple Fibroblast Growth Factor Responses during Early Mouse Development
Mol. Cell. Biol., May 15, 2005; 25(10): 4105 - 4116.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
T. Kunath, D. Arnaud, G. D. Uy, I. Okamoto, C. Chureau, Y. Yamanaka, E. Heard, R. L. Gardner, P. Avner, and J. Rossant
Imprinted X-inactivation in extra-embryonic endoderm cell lines from mouse blastocysts
Development, April 1, 2005; 132(7): 1649 - 1661.
[Abstract] [Full Text] [PDF]


Home page
J. Virol.Home page
M. Djavani, I. Topisirovic, J. C. Zapata, M. Sadowska, Y. Yang, J. Rodas, I. S. Lukashevich, C. W. Bogue, C. D. Pauza, K. L. B. Borden, et al.
The Proline-Rich Homeodomain (PRH/HEX) Protein Is Down-Regulated in Liver during Infection with Lymphocytic Choriomeningitis Virus
J. Virol., February 15, 2005; 79(4): 2461 - 2473.
[Abstract] [Full Text] [PDF]


Home page
Genes Dev.Home page
A. C. Foley and M. Mercola
Heart induction by Wnt antagonists depends on the homeodomain transcription factor Hex
Genes & Dev., February 1, 2005; 19(3): 387 - 396.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
H. Hallaq, E. Pinter, J. Enciso, J. McGrath, C. Zeiss, M. Brueckner, J. Madri, H. C. Jacobs, C. M. Wilson, H. Vasavada, et al.
A null mutation of Hhex results in abnormal cardiac development, defective vasculogenesis and elevated Vegfa levels
Development, October 15, 2004; 131(20): 5197 - 5209.
[Abstract] [Full Text] [PDF]


Home page
Endocr. Rev.Home page
M. De Felice and R. Di Lauro
Thyroid Development and Its Disorders: Genetics and Molecular Mechanisms
Endocr. Rev., October 1, 2004; 25(5): 722 - 746.
[Abstract] [Full Text] [PDF]


Home page
J. Cell Biol.Home page
J. Takito and Q. Al-Awqati
Conversion of ES cells to columnar epithelia by hensin and to squamous epithelia by laminin
J. Cell Biol., September 27, 2004; 166(7): 1093 - 1102.
[Abstract] [Full Text] [PDF]


Home page
EndocrinologyHome page
M. De Felice, M. P. Postiglione, and R. Di Lauro
Minireview: Thyrotropin Receptor Signaling in Development and Differentiation of the Thyroid Gland: Insights from Mouse Models and Human Diseases
Endocrinology, September 1, 2004; 145(9): 4062 - 4067.
[Full Text] [PDF]


Home page
Arterioscler. Thromb. Vasc. Bio.Home page
Y. Oyama, K. Kawai-Kowase, K. Sekiguchi, M. Sato, H. Sato, M. Yamazaki, Y. Ohyama, Y. Aihara, T. Iso, E. Okamaoto, et al.
Homeobox Protein Hex Facilitates Serum Responsive Factor-Mediated Activation of the SM22{alpha} Gene Transcription in Embryonic Fibroblasts
Arterioscler. Thromb. Vasc. Biol., September 1, 2004; 24(9): 1602 - 1607.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
T. E. Swingler, K. L. Bess, J. Yao, S. Stifani, and P.-S. Jayaraman
The Proline-rich Homeodomain Protein Recruits Members of the Groucho/Transducin-like Enhancer of Split Protein Family to Co-repress Transcription in Hematopoietic Cells
J. Biol. Chem., August 13, 2004; 279(33): 34938 - 34947.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
G. C. Chu, N. R. Dunn, D. C. Anderson, L. Oxburgh, and E. J. Robertson
Differential requirements for Smad4 in TGF{beta}-dependent patterning of the early mouse embryo
Development, August 1, 2004; 131(15): 3501 - 3512.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
O. G. Kelly, K. I. Pinson, and W. C. Skarnes
The Wnt co-receptors Lrp5 and Lrp6 are essential for gastrulation in mice
Development, June 15, 2004; 131(12): 2803 - 2815.
[Abstract] [Full Text] [PDF]


Home page
Circ. Res.Home page
K. Ihida-Stansbury, D. M. McKean, S. A. Gebb, J. F. Martin, T. Stevens, R. Nemenoff, A. Akeson, J. Vaughn, and P. L. Jones
Paired-Related Homeobox Gene Prx1 Is Required for Pulmonary Vascular Development
Circ. Res., June 11, 2004; 94(11): 1507 - 1514.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
S. Srinivas, T. Rodriguez, M. Clements, J. C. Smith, and R. S. P. Beddington
Active cell migration drives the unilateral movements of the anterior visceral endoderm
Development, March 1, 2004; 131(5): 1157 - 1164.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
R. Bort, J. P. Martinez-Barbera, R. S. P. Beddington, and K. S. Zaret
Hex homeobox gene-dependent tissue positioning is required for organogenesis of the ventral pancreas
Development, February 15, 2004; 131(4): 797 - 806.
[Abstract] [Full Text] [PDF]


Home page
J BiochemHome page
A. Sato, V. W. Keng, T. Yamamoto, S. Kasamatsu, T. Ban, H. Tanaka, S.-i. Satoh, K. Yamada, and T. Noguchi
Identification and Characterization of the Hematopoietic Cell-Specific Enhancer-Like Element of the Mouse Hex Gene
J. Biochem., February 1, 2004; 135(2): 259 - 268.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
L. Zakin and E. M. De Robertis
Inactivation of mouse Twisted gastrulation reveals its role in promoting Bmp4 activity during forebrain development
Development, January 15, 2004; 131(2): 413 - 424.
[Abstract] [Full Text] [PDF]


Home page
Mol. Cell. Biol.Home page
I. Topisirovic, M. L. Guzman, M. J. McConnell, J. D. Licht, B. Culjkovic, S. J. Neering, C. T. Jordan, and K. L. B. Borden
Aberrant Eukaryotic Translation Initiation Factor 4E-Dependent mRNA Transport Impedes Hematopoietic Differentiation and Contributes to Leukemogenesis
Mol. Cell. Biol., December 15, 2003; 23(24): 8992 - 9002.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
C. Haumaitre, M. Reber, and S. Cereghini
Functions of HNF1 Family Members in Differentiation of the Visceral Endoderm Cell Lineage
J. Biol. Chem., October 17, 2003; 278(42): 40933 - 40942.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
J. Palis
Putting a Hex on blood and endothelium
Blood, October 1, 2003; 102(7): 2315 - 2316.
[Full Text] [PDF]


Home page
BloodHome page
Y. Guo, R. Chan, H. Ramsey, W. Li, X. Xie, W. C. Shelley, J. P. Martinez-Barbera, B. Bort, K. Zaret, M. Yoder, et al.
The homeoprotein Hex is required for hemangioblast differentiation
Blood, October 1, 2003; 102(7): 2428 - 2435.
[Abstract] [Full Text] [PDF]


Home page
Genes Dev.Home page
S. D. Vincent, N. R. Dunn, S. Hayashi, D. P. Norris, and E. J. Robertson
Cell fate decisions within the mouse organizer are governed by graded Nodal signals
Genes & Dev., July 1, 2003; 17(13): 1646 - 1662.
[Abstract] [Full Text] [PDF]


Home page
Nucleic Acids ResHome page
C. Puppin, A. V. D'Elia, L. Pellizzari, D. Russo, F. Arturi, I. Presta, S. Filetti, C. W. Bogue, L. A. Denson, and G. Damante
Thyroid-specific transcription factors control Hex promoter activity
Nucleic Acids Res., April 1, 2003; 31(7): 1845 - 1852.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
D. P. Norris, J. Brennan, E. K. Bikoff, and E. J. Robertson
The Foxh1-dependent autoregulatory enhancer controls the level of Nodal signals in the mouse embryo
Development, March 9, 2003; 129(14): 3455 - 3468.
[Abstract] [Full Text] [PDF]


Home page
Arterioscler. Thromb. Vasc. Bio.Home page
T. Nakagawa, M. Abe, T. Yamazaki, H. Miyashita, H. Niwa, S. Kokubun, and Y. Sato
HEX Acts as a Negative Regulator of Angiogenesis by Modulating the Expression of Angiogenesis-Related Gene in Endothelial Cells In Vitro
Arterioscler. Thromb. Vasc. Biol., February 1, 2003; 23(2): 231 - 237.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
W. Zhang, T. A. Yatskievych, X. Cao, and P. B. Antin
Regulation of Hex Gene Expression by a Smads-dependent Signaling Pathway
J. Biol. Chem., November 15, 2002; 277(47): 45435 - 45441.
[Abstract] [Full Text] [PDF]


Home page
Cancer Res.Home page
T. Hamamoto, H. Beppu, H. Okada, M. Kawabata, T. Kitamura, K. Miyazono, and M. Kato
Compound Disruption of Smad2 Accelerates Malignant Progression of Intestinal Tumors in Apc Knockout Mice
Cancer Res., October 15, 2002; 62(20): 5955 - 5961.
[Abstract] [Full Text] [PDF]


Home page
Genes Dev.Home page
L. A. Hanna, R. K. Foreman, I. A. Tarasenko, D. S. Kessler, and P. A. Labosky
Requirement for Foxd3 in maintaining pluripotent cells of the early mouse embryo
Genes & Dev., October 15, 2002; 16(20): 2650 - 2661.
[Abstract] [Full Text] [PDF]


Home page
Stem CellsHome page
B. M. Owens and R. G. Hawley
HOX and Non-HOX Homeobox Genes in Leukemic Hematopoiesis
Stem Cells, September 1, 2002; 20(5): 364 - 379.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
T. Wendl, K. Lun, M. Mione, J. Favor, M. Brand, S. W. Wilson, and K. B. Rohr
pax2.1 is required for the development of thyroid follicles in zebrafish
Development, August 1, 2002; 129(15): 3751 - 3760.
[Abstract] [Full Text] [PDF]


Home page
J. Clin. Endocrinol. Metab.Home page
A. V. D'Elia, G. Tell, D. Russo, F. Arturi, F. Puglisi, G. Manfioletti, V. Gattei, D. L. Mack, P. Cataldi, S. Filetti, et al.
Expression and Localization of the Homeodomain-Containing Protein HEX in Human Thyroid Tumors
J. Clin. Endocrinol. Metab., March 1, 2002; 87(3): 1376 - 1383.
[Abstract] [Full Text] [PDF]


Home page
J. Clin. Endocrinol. Metab.Home page
A. Olivieri, M. A. Stazi, P. Mastroiacovo, C. Fazzini, E. Medda, A. Spagnolo, S. De Angelis, M. E. Grandolfo, D. Taruscio, V. Cordeddu, et al.
A Population-Based Study on the Frequency of Additional Congenital Malformations in Infants with Congenital Hypothyroidism: Data from the Italian Registry for Congenital Hypothyroidism (1991-1998)
J. Clin. Endocrinol. Metab., February 1, 2002; 87(2): 557 - 562.
[Abstract] [Full Text] [PDF]


Home page
J. Cell Sci.Home page
T. A. Pelton, S. Sharma, T. C. Schulz, J. Rathjen, and P. D. Rathjen
Transient pluripotent cell populations during primitive ectoderm formation: correlation of in vivo and in vitro pluripotent cell development.
J. Cell Sci., January 15, 2002; 115(2): 329 - 339.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
K. Piotrowska, F. Wianny, R. A. Pedersen, and M. Zernicka-Goetz
Blastomeres arising from the first cleavage division have distinguishable fates in normal mouse development
Development, October 1, 2001; 128(19): 3739 - 3748.
[Abstract] [Full Text] [PDF]


Home page
Genes Dev.Home page
S. A. Duncan and A. J. Watt
BMPs on the road to hepatogenesis
Genes & Dev., August 1, 2001; 15(15): 1879 - 1884.
[Full Text] [PDF]


Home page
Genes Dev.Home page
M. Yamamoto, C. Meno, Y. Sakai, H. Shiratori, K. Mochida, Y. Ikawa, Y. Saijoh, and H. Hamada
The transcription factor FoxH1 (FAST) mediates Nodal signaling during anterior-posterior patterning and node formation in the mouse
Genes & Dev., May 15, 2001; 15(10): 1242 - 1256.
[Abstract] [Full Text]


Home page
Genes Dev.Home page
P. A. Hoodless, M. Pye, C. Chazaud, E. Labbé, L. Attisano, J. Rossant, and J. L. Wrana
FoxH1 (Fast) functions to specify the anterior primitive streak in the mouse
Genes & Dev., May 15, 2001; 15(10): 1257 - 1271.
[Abstract] [Full Text]


Home page
Cardiovasc ResHome page
E. M. Conway, D. Collen, and P. Carmeliet
Molecular mechanisms of blood vessel growth
Cardiovasc Res, February 16, 2001; 49(3): 507 - 521.
[Full Text] [PDF]


Home page
Circ. Res.Home page
D. H. Gorski and K. Walsh
Control of Vascular Cell Differentiation by Homeiobox Transcription Factors
Circ. Res., January 19, 2001; 88(1): 7 - 8.
[Full Text] [PDF]


Home page
Circ. Res.Home page
K. Sekiguchi, M. Kurabayashi, Y. Oyama, Y. Aihara, T. Tanaka, H. Sakamoto, Y. Hoshino, T. Kanda, T. Yokoyama, Y. Shimomura, et al.
Homeobox Protein Hex Induces SMemb/Nonmuscle Myosin Heavy Chain-B Gene Expression Through the cAMP-Responsive Element
Circ. Res., January 19, 2001; 88(1): 52 - 58.
[Abstract] [Full Text] [PDF]


Home page
DevelopmentHome page
L. Lowe, S Yamada, and M. Kuehn
Genetic dissection of nodal function in patterning the mouse embryo
Development, January 5, 2001; 128(10): 1831 - 1843.
[Abstract] [PDF]


Home page
DevelopmentHome page
A Perea-Gomez, K. Lawson, M Rhinn, L Zakin, P Brulet, S Mazan, and S. Ang
Otx2 is required for visceral endoderm movement and for the restriction of posterior signals in the epiblast of the mouse embryo
Development, January 3, 2001; 128(5): 753 - 765.
[Abstract] [PDF]


Home page
Circ. Res.Home page
D. H. Gorski and K. Walsh
The Role of Homeobox Genes in Vascular Remodeling and Angiogenesis
Circ. Res., November 10, 2000; 87(10): 865 - 872.
[Abstract] [Full Text] [PDF]