Cry genes

Subsequent studies revealed that the transcription of Rev-erba, is regulated by essentially the same mechanisms as those of Per and Cry genes it is activated by BMALl and CLOCK and repressed by PER and CRY. Therefore, REV-ERBa directly connects two antiphasic feedback loops within the positive and negative limbs of the oscillator (Fig. 1). 

The genes responsible for the crystal proteins are called cry genes, and the crystal toxin is called 5-endotoxin or Cry toxin, whereas the genes responsible for toxic cytosolic proteins (Cyt toxins) are called cyt genes. Many Bt strains are able to produce a number of such smaller cytosolic endotoxins in addition to the 8-endotoxins, but these are often deposited in inclusion bodies inside the crystals where they can comprise a considerable part of the crystal. Unlike the Cry toxins, the other toxins display a broader unspecific activity and may have some mammalian toxicity. They include the P-exotoxins, hemolysins, and enterotoxins. 

Best known as genes conveying new properties are the EPSPS gene from the plant Petunia hybrida, which codes for tolerance to the herbicide Roundup Ready [this is found in the Roundup Ready soybean (RRS)], and the cry genes from Bacillus... 

When tested under agronomic conditions in the field, transgenic tomato [35] and tobacco plants [36] expressing truncated cry genes showed substantial levels of insecticidal activity against their primary pest insects. Yet, it became apparent that, for certain crops or insect pests, higher Cry protein expression levels were needed to achieve complete insect control in the field. Typically, expression levels of native truncated cry genes in plants, usually about 0.001% of total soluble pro-... 

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