Sonic The Hedgehog

Dr. A. Jamie Cuticchia jamie at
Mon Apr 8 07:03:16 EST 1996

Jason Ploof wrote:
> I am a first year college biology student and have been given
> the assignment;  Find out what Sonic the Hedgehog is.  No,
> not the video game.  It is something related to biology.
> Help!!!!!

This is taken from the Online version of Mendelian Inheritance in Man.
This resource is available from the NCBI at:

A. Jamie Cuticchia


Gene Map Locus: 7q36 

Note: pressing the  symbol will find the citations in the NCBI MEDLINE 
subset whose text most closely matches the
text of the preceding OMIM paragraph, using the Entrez MEDLINE 
neighboring function. 


The organization and morphology of the developing embryo are established 
through a series of inductive interactions
(Marigo et al., 1995). One family of vertebrate genes has been described 
related to the Drosophila gene 'hedgehog' (hh)
that encodes inductive signals during embryogenesis (Echelard et al., 
1993; Roelink et al., 1994). 'Hedgehog' encodes a
secreted protein that is involved in establishing cell fates at several 
points during Drosophila development. There are 3
known mammalian homologs of hh: sonic hedgehog (Shh), Indian hedgehog 
(Ihh), and desert hedgehog (Dhh)
(Echelard et al., 1993). Like its Drosophila cognate, Shh encodes a 
signal that is instrumental in patterning the early
embryo. It is expressed in Hensen's node, the floorplate of the neural 
tube, the early gut endoderm, the posterior of the
limb buds, and throughout the notochord. It has been implicated as the 
key inductive signal in patterning of the ventral
neural tube (Echelard et al., 1993; Roelink et al., 1994), the 
anterior-posterior limb axis (Riddle et al., 1993), and the
ventral somites (Johnson et al., 1994).  

The mouse, chicken, and zebrafish Shh homologs are highly conserved 
(Marigo et al., 1995). Their functional properties
appear to be conserved as well. Their probable importance in 
embryogenesis additionally suggests that alterations in
the human hedgehog genes might be involved in congenital anomalies. 
Marigo et al. (1995) isolated human cDNA
clones of the SHH and IHH (600726) genes. The SHH clone encoded a 
protein 92.4% identical to its mouse homolog.
The IHH clone encoded a protein 94.6% identical to its mouse homolog. 
IHH was expressed in adult kidney and liver.
SHH expression was not detected in adult tissues examined; however, it 
was expressed in fetal intestine, liver, lung, and
kidney. By PCR analysis of DNA from a panel of rodent/human somatic cell 
hybrids, Marigo et al. (1995) assigned SHH
to 7q and IHH to chromosome 2. SHH was more precisely localized by 
linkage studies using a CA repeat sequence
tagged site identified in a P1 genomic clone of SHH in members of a 
family with polysyndactyly (triphalangeal
thumb-polysyndactyly syndrome (TPT1); 190605) previously reported by 
Tsukurov et al. (1994). SHH was found to be
closely linked but distinct from the TPT1 locus at 7q36; maximum lod 
score = 4.82 at theta = 0.05. It was tightly linked to
the engrailed-2 locus (EN2; 131310). Marigo et al. (1995) mapped the 
mouse homologs Shh, Ihh, and Dhh by linkage
analysis of an interspecific backcross. Shh mapped to a position 0.6 cM 
distal to En2 and 1.9 cM distal to Il6 (IL6;
147620) on mouse chromosome 5. This location is closely linked but 
distinct from the murine limb mutation Hx and is in
an area with homology of synteny to human 7q36.  


1. Echelard, Y.; Epstein, D. J.; St-Jacques, B.; Shen, L.; Mohler, J.; 
McMahon, J. A.; McMahon, A. P. : 
     Sonic hedgehog, a member of a family of putative signaling 
molecules, is implicated in the regulation of CNS
     polarity. Cell 75: 1417-1430, 1993. 
     MEDLINE UID : 94094334

2. Johnson, R. L.; Laufer, E.; Riddle, R. D.; Tabin, C. : 
     Ectopic expression of Sonic hedgehog alters dorsal-ventral 
patterning of somites.. Cell 79: 1165-1173, 1994. 
     MEDLINE UID : 95094292

3. Marigo, V.; Roberts, D. J.; Lee, S. M. K.; Tsukurov, O.; Levi, T.; 
Gastier, J. M.; Epstein, D. J.; Gilbert, D. J.; Copeland, N.
G.; Seidman, C. E.; Jenkins, N. A.; Seidman, J. G.; McMahon, A. P.; 
Tabin, C. : 
     Cloning, expression, and chromosomal location of SHH and IHH: two 
human homologues of the Drosophila
     segment polarity gene hedgehog. Genomics 28: 44-51, 1995. 
     MEDLINE UID : 96070431

4. Riddle, R. D.; Johnson, R. L.; Laufer, E.; Tabin, C. : 
     Sonic hedgehog mediates the polarizing activity of the ZPA. Cell 
75: 1401-1416, 1993. 
     MEDLINE UID : 94094333

5. Roelink, H.; Augsburger, A.; Heemskerk, J.; Korzh, V.; Norlin, S.; 
Ruiz i Altaba, A.; Tanabe, Y.; Placzek, M.; Edlund, T.;
Jessell, T. M.; Dodd, J. : 
     Floor plate and motor neuron induction by vhh-1, a vertebrate 
homolog of hedgehog expressed by the
     notochord. Cell 76: 761-775, 1994. 
     MEDLINE UID : 94170375

6. Tsukurov, O.; Boehmer, A.; Flynn, J.; Nicolai, J.-P.; Hamel, B. C. 
J.; Traill, S.; Zaleske, D.; Mankin, H. J.; Yeon, H.; Ho, C.;
Tabin, C.; Seidman, J. G.; Seidman, C. : 
     A complex bilateral polysyndactyly disease locus maps to chromosome 
7q36. Nature Genet. 6: 282-286, 1994.

     MEDLINE UID : 94282077


Victor A. McKusick : 8/17/1995 


terry : 9/11/1995 
mark : 8/17/1995 

 A. Jamie Cuticchia, Ph.D.               | 703.610.2127 (voice)
 Director, Computational Biology         | 703.610.1561 (fax)
 Mitretek Systems                        | 
 7525 Colshire Dr., McLean VA 22102-7400 | jamie at

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