Achaete-scute

AS-C achaete-scute gene complex for sense organs CLN neuronal ceroid lipofuscinoses... 

The expression of neuro D1 and mammalian achaete-scute complex-like protein (MASH) have been assessed in gastroenteropancreatic (GEP) tumors.These studies have demonstrated that MASH-1 is highly expressed in poorly differentiated GEP tumors, whereas neuroDl is present in all well-differentiated carcinomas and tumors. Interestingly, low levels of neuroDl expression were seen in approximately one third of poorly differentiated GEP carcinomas and this feature was associated with a significantly shorter overall survival. 

An additional approach to the distinction of Merkel cell tumors from small cell pulmonary carcinomas involves the use of antibodies to the mammalian achaete-scute complex-like protein (MASH). Although more than 80% of small cell pulmonary carcinomas are MASH positive, only 1 of 30 Merkel cell carcinomas was positive for this marker. Merkel cell carcinomas also express the K homology domain containing protein (KOC), similar to other high-grade NE malignancies. 

The protein product of the human homolog of the Drosophila achaete-scute gene provides a good example of an LCR-containing protein. When analyzed with seg, two regions of low compositional complexity were identified. Figure 8.12a shows... 

Achaete-scute. These basic helix-loop-helix (bHLH) proteins appear in primordial nerve cells (chaeta, chaete, long filament, or bristie scute, scale or homy plate dipteran bristles, lepidopteran wing scales. Drosophila melanogaster, Bombyx... 

Human primitive neuroectodermal mmors (PNETs) originate frequentiy in a bone (see in Introduction), show the Ewing s sarcoma gene translocation (22ql2), express the achaete-scute gene-product proteins (mammalian achaete-scute-Uke homolog, ASH, ASCL, Mash), and have the bad reputation to be combination chemotherapy-resistant with frequent relapses. 

Some poorly differentiated human sinonasal neoplasms (neuroblastoma, neuroectodermal mmors) express the ancient achaete-scute genes/gene-product proteins. This finding was interpreted as a nonspecific marker for diagnosis [1751, 1752]. Esthesioneuroblastoma of the nasal cavity and the paranasal sinuses express upregulated Mashl [1753, 1754]. The Mash proteins may be the driving force of these mmors. 

Transdifferentiation of geno-phenotypes. A highly recognized promoter of neuroendocrine transdifferentiation of adenocarcinoma cells is the achaete scute pathway [1711, 1712, 1755] (Table XXDC). 

Layden MJ, Boekhout M, Maitindale MQ. Nematostella vectensis achaete-scute homolog NvAshA regulates embryonic ectodermal neurogenesis and represents an ancient component of the metazoan neural specification pathway. Development. 2012 139 1013-22. 

Grens A, Mason E, Marsh JL, Bode HR. Evolutionary conservation of a cell fate specification gene the Hydra achaete-scute homolog has proneural activity in Drosophila. Development. 1995 121 4027-35. 

Simionato D, Kemer P, Dray NJ, Le Gouar M, Ledent V, Arendt D, Vervoort M. Achaete-scute-related genes in the Platynereis dumeilii insights into the evolution of neural basic helix-loop-helix genes. BMC Evol Biol. 2008 8 170. doi 10.1186/1471-2148-8-170/. 

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