SCA

SCA may refer to:

Organizations

Locations

Shuttle Carrier Aircraft

The Shuttle Carrier Aircraft (SCA) were two extensively modified Boeing 747 airliners that NASA used to transport Space Shuttle orbiters. One is a 747-100 model, while the other is a short range 747-100SR.

The SCAs were used to ferry Space Shuttles from landing sites back to the Shuttle Landing Facility at the Kennedy Space Center, and to and from other locations too distant for the orbiters to be delivered by ground transport. The orbiters were placed on top of the SCAs by Mate-Demate Devices, large gantry-like structures that hoisted the orbiters off the ground for post-flight servicing then mated them with the SCAs for ferry flights.

In approach and landing test flights conducted in 1977, the test shuttle Enterprise was released from an SCA during flight and glided to a landing under its own control.

Design and development

The Lockheed C-5 Galaxy was considered for the shuttle-carrier role by NASA, but rejected in favor of the 747—in part due to the 747's low-wing design in comparison to the C-5's high-wing design, and also because the U.S. Air Force would have retained ownership of the C-5, while NASA could own the 747s outright.

ATXN8OS

Ataxin 8 opposite strand, also known as ATXN8OS, is a human gene.

Function

SCA8 is an antisense transcript to the KLHL1 gene (homolog to the Drosophila KELCH gene); it does not itself appear to be protein coding. A CTG trinucleotide repeat expansion that is incorporated into the SCA8 but not the KLHL1 transcript causes spinocerebellar ataxia type 8. Presumably the expansion interferes with normal antisense function of this transcript.

References

Further reading

External links

Sca-1

Sca-1 stands for "Stem cells antigen-1". It consist of 18-kDa mouse glycosyl phosphatidylinositol-anchored cell surface protein (GPI-AP) of the LY6 gene family. It is the common biological marker used to identify hematopoitic stem cell (HSC) along with other markers.

Application of Sca-1

References

PPP2R2B

Serine/threonine-protein phosphatase 2A 55 kDa regulatory subunit B beta isoform is an enzyme that in humans is encoded by the PPP2R2B gene.

The product of this gene belongs to the phosphatase 2regulatory subunit B family. Protein phosphatase 2 is one of the four major Ser/Thr phosphatases, and it is implicated in the negative control of cell growth and division. It consists of a common heteromeric core enzyme, which is composed of a catalytic subunit and a constant regulatory subunit, that associates with a variety of regulatory subunits. The B regulatory subunit might modulate substrate selectivity and catalytic activity. This gene encodes a beta isoform of the regulatory subunit B55 subfamily. Defects in the 5' UTR of this gene may cause a rare form of autosomal dominant spinocerebellar ataxia 12.

References

Further reading

External links

Machado–Joseph disease

Machado–Joseph disease (MJD), also known as Machado–Joseph Azorean disease or Joseph's disease or Spinocerebellar ataxia type 3 (SCA3), is a rare autosomal, dominantly inherited neurodegenerative disease that causes progressive cerebellar ataxia,which results in a lack of muscle control and coordination of the upper and lower extremities. The symptoms are caused by a genetic mutation that results in an expansion of abnormal "CAG" trinucleotide repeats in the ATXN3 gene that results in an abnormal form of the protein ataxin which causes degeneration of cells in the hindbrain. Some symptoms, such as clumsiness and rigidity, make MJD commonly mistaken for drunkenness and/or Parkinson's disease.

Machado–Joseph disease is a type of spinocerebellar ataxia and is the most common cause of autosomal-dominant ataxia. MJD causes ophthalmoplegia and mixed sensory and cerebellar ataxia.

History

The disease was first identified in 1972.

Unlike many other medical conditions, Machado–Joseph disease isn't named after researchers. It is named after two men ("William Machado" and "Antone Joseph") who were the patriarchs of the families in which the condition was initially described. The above families are of Azorean descent, an ethnic group in which the disease is most prevalent. The highest prevalence of the condition is on the Azorean island of Flores where around 1 in 140 individuals in the population are diagnosed with MJD.