등쪽신경관에서 Gli3의 역할 = Roles of Gli3 in Dorsal Neural Tube

국문 초록 (Abstract)

배쪽신경관 형성에 있어 Gli3의 필수적인 역할은 Shh-/- 생쥐나 Shh-/-;Gli3-/- 생쥐 등의 연구를 통해 잘 알려져 있다. 그러나 Gli3가 등쪽신경관에 많이 발현되고 있음에도 불구하고 그 역할이 아직 명확하지 않다.
본 연구에서는 등쪽신경관에서 Gli3의 역할을 구명하기 위하여 Gli3-/-생쥐의 등쪽신경관 발생을 관찰하였다.
Phosphohistone 3에 대한 면역조직화학법과 BrdU 실험을 통하여 세포분열을 조사하였을 때 Gli3-/- 생쥐의 등쪽신경관에서 세포분열이 정상 생쥐에 비해서 증가하였다. 세포주기를 벗어난, 신경세포와 dI3 사이신경세포에서 각각 발현되는 HuC/D와 Isl1은 Gli3-/- 생쥐에서 정상 생쥐에 비해서 그 발현이 지연되었다. 전구세포에서 신경세포로의 분화를 유도하는 Ngn2의 발현도 Gli3-/- 생쥐에서 정상 생쥐에 비해서 지연되었다. HuC/D, Isl1 그리고 Ngn2의 발현 결과들은 Gli3-/- 생쥐의 등쪽신경관에서 신경분화가 지연되었음을 의미한다. 이상의 결과들는 Gli3가 등쪽신경관에서 신경전구세포의 세포분열과 분화에 관여함을 의미한다.

다국어 초록 (Multilingual Abstract)

Essential roles of Gli3 in ventral neural tube have been stressed from studies of Shh-/- and Shh-/-; Gli3-/- mutants. However, roles of Gli3 in dorsal neural tube have not been fully appreciated despite of its high
expression. To find out roles of Gli3 in dorsal neural tube, we studied cell proliferation and neuronal differentiation in dorsal neural tube of Gli3-/- mutant. In Gli3-/- mutant, proliferation of progenitor cells in dorsal neural tube is increased compared to wild type embryos based on phosphohistone 3 immunohistochemistry and BrdU experiment.
The appearances of HuC/D positive and Isl1 postive cells which represent postmitotic neurons and dI3 interneurons were delayed in Gli3-/- mutant compared to wild type embryo. The appearance of a proneural gene, Ngn2 was also delayed in Gli3-/- mutant compared to wild type embryo. Neuronal differentiation of progenitor cells in dorsal neural tube was delayed in Gli3-/- mutant compared to wild type embryos based on HuC/D, Isl1 and Ngn2 expressions.
These results suggest that Gli3 plays important roles in cell proliferation and neuronal differentiation in dorsal neural tube. Thus our data shed a new light on the role of Gli3 in the development of neural tube.

참고문헌 (Reference)

1 "is expressed during normal mouse development" a zinc finger transcription factor and oncogene 91-102, 1993

2 "and spinal cord identity in gastrula stage chick embryos" 689-23 702, 1999

3 "and differentiation during mouse lung organo-genesis" 270 : 214-231, 2004

4 "Widespread requirement for Hedgehog ligand stimulation in growth of digestive tract tumours" 425 : 846-425 851, 2003

5 "Tissue repair and stem cell renewal in carcinogenesis" 331 : 324-432 331, 2004

6 "The specification of dorsal cell fates in the vertebrate central nervous system" 22 : 261-294, 1999

7 "The paired homeodomain protein DRG11 is required for the projection of cutaneous sensory afferent fibers to the dorsal spinal cord" 31 : 59-31 73, 2001

8 "The homeodomain factor lbx1 distinguishes two major programs of neuronal differentiation in the dorsal spinal cord" 551-34 562, 2002

9 "Specification of neuronal cell types in the ventral spinal cord is mediated by antagonistic interaction between Shh and Gli3" 979-985, 2000

10 "Sonic hedgehog opposes epithelial cell cycle arrest" 71-76, 1999

11 "Signaling through BMP type 1 receptors is required for development of interneuron cell types in the dorsal spinal cord" 131 : 5393-131 5403, 2004

12 "Sequential actions of BMP receptors control neural precursor cell production and fate" 2094-2110, 2001

13 "Regulation of cerebral cortical size by control of cell cycle exit in neural precursors" 297 : 365-297 9, 2002

14 "Regulation of NIH-3T3 cell G1 phase transit by serum during exponential growth" 511-524, 1995

15 "Proprioceptor pathway development is dependent on Math1" 411-30 422, 2001

16 "Proper development of relay somatic sensory neurons and D2/D4 interneurons requires homeobox genes Rnx/Tlx-3 and Tlx-1" 1220-1233, 2002

17 "Proneural genes and the specification of neural cell types" 3 : 517-530, 2002

18 "Patterning cell types in the dorsal spinal cord" 4 : 289-297, 2003

19 "Patched1 interacts with cyclin B1 to regulate cell cycle progression" 2214-2223, 2001

20 "Overlapping expression domains of bone morphogenetic protein family members potentially account for limited tissue defects in BMP7 deficient embryos" 349-62, 1997

21 "Neuronal specification in the spinal cord" 20-9, 2000

22 "Neuronal patterning by BMPs a requirement for GDF7 in the generation of a discrete class of commissural interneurons in the mouse spinal cord" 3394-3407, 1998

23 "Neurogenin1 and neurogenin2 control two distinct waves of neurogenesis in developing dorsal root ganglia" 1717-1728, 1999

24 "Lbx1 specifies somatosensory association interneurons in the dorsal spinal cord" 34 : 535-34 549, 2002

25 "Hedgehog-regulated processing of Gli3 roduces an anterior/posterior repressor gradient in the developing vertebrate limb" 423-434, 2000

26 "Hedgehog signalling within airway epithelial progenitorsand in small-cell lung cancer" 313-422 317, 2003

27 "Hedgehog signaling in animal development" paradigms and principles 3059-3087, 2001

28 "Hedgehog regulates cell growth and proliferation by inducing Cyclin D and Cyclin E" 299-417 304, 2002

29 "Hedgehog is an early and late mediator of pancreatic cancer tumorigenesis" 851-425 856, 2003

30 "Expression of three mouse homologs of the Drosophila segment polarity gene cubitus interruptus in ectoderm- and mesoderm-derived tissues suggests multiple roles during postimplantation development" 402-2 3 413, 1994

31 "Expression of the mouse Gli and Ptc genes is adjacent to embryonic sources of hedgehog signals suggesting a conservation of pathways between flies and mice" 121-135, 1997

32 "Early stages of motor neuron differentiation revealed by expression of homeobox gene Islet-1" 1555-256 1560, 1992

33 "Dorsal-ventral patterning of the spinal cord requires Gli3 transcriptional repressor activity" 2865-2878, 2002

34 "Dorsal differentiation of neural plate cells induced by BMP-mediated signals from epidermal ectoderm" 969-979, 1995

35 "Crossinhibitory activities of Ngn1 and Math1 allow specification of distinct dorsal interneurons" 219-31 232, 2001

36 "Carboxy-terminally truncated Gli3 proteins associate with Smads" 325-326, 1998

37 "Bone morphogenetic protein-4 is required for mesoderm formation and patterning in the mouse" 2105-2116, 1995

38 "BMP-7 is an inducer of nephrogenesis and is also required for eye development and skeletal patterning" 2808-2820, 1995

39 "A role for the roof plate and its resident TGFbeta-related proteins in neuronal patterning in the dorsal spinal cord" 91 : 127-138, 1997

40 "A requirement for bone morphogenetic protein-7 during development of the mammalian kidney and eye" 2795-2807, 1995

41 "A homeodomain protein code specifies progenitor cell identity and neuronal fate in the ventral neural tube" 435-445, 2000

42 "A binding site for Gli proteins is essential for HNF-3beta floor plate enhancer activity in transgenics and can respond to Shh in vitro" 1313-124 1322, 1997