Arabidopsis Gene AS1 and AS2 Mutations and Their Impacts on Protein Structure

Specific borders separating the developing organ primordium from the surrounding tissues can be seen in plants like the Arabidopsis (Vu, Ondar and Soldatova 11). For the appropriate development of the organs, such actions necessitate the effect of specific genes. By suppressing boundary-specific genes like the KNOX genes, the ASYMMETRIC LEAVES 1 and 2 (AS1 and AS2) genes in the Arabidopsis thaliana aid in the healthy growth of the organs (Chapman and Brown 224). For the organs to develop properly, these genes must continue to be silenced. Normally, the KNOX gene cannot be expressed due to AS1 and AS2 expression. However if the AS1 and AS2 genes are mutated, the KNOX gene manifests itself, and this result in the development of wrinkled leaves, curled leaves, and even short poorly formed petioles. The AS1 encodes typically for an R2-R3 myb domain transcription factor 3 which are members of a large gene family in the Arabidopsis. The R2-R3 myb proteins usually bind to the DNA and function in several cellular processes. The AS2, on the other hand, encodes for a protein that contains both the leucine-zipper-like and zinc figure motif and also binds on the DNA. It is mainly expressed on the adaxial side of the cotyledons and is the one responsible for the development of wrinkled leaves in the Arabidopsis and also lead to the development of the leaf-like structures from the petioles (Chapman and Brown 223). The figure below shows the typical AS1 and AS2 proteins. (Li et al.964)



Source: https://d2ufo47lrtsv5s.cloudfront.net/content/sci/early/2017/05/17/science.aah6345/F3.large.jpg

However, mutations can sometimes occur which may include deletions or duplication of genes and hence resulting in a total change in the structure of the protein. In this case, the binding domains of the protein are affected, and therefore the overall function of the protein will be changed as well. To determine the presence of such mutations in the DNA which could either be deletions or duplications, we run the sequence of the wild-type and that of the mutant. The genome of the wild-type has about 42 genes (Li et al. 960).When the sequence of the normal compared to that of the mutant, variations in some regions were observed.The sequence or the gene affected was then identified using sequence-specific probes that hybridize readily to the target sequence. The mutant one indicated an overexpression, i.e., duplication in the KNOX gene. It was expected that once the KNOX genes are overexpressed, they suppress the effects of the AS1 and AS2 genes and hence leading to the development of the wrinkled leaves with short petioles and thus the appearance of the as1 and as2 phenotypes.



















































Works Cited

Chapman, Bernice, and Chris Brown. "Translation Termination In Arabidopsis Thaliana: Characterisation Of Three Versions Of Release Factor 1." Gene 341 (2004): 219-225. Web.

Li, Zhongfei, et al. "Transcription Factors AS1 And AS2 Interact With LHP1 To Repressknoxgenes Arabidopsis." Journal of Integrative Plant Biology 58.12 (2016): 959-970. Web.

Vu, H. T., U. N. Ondar, and O. P. Soldatova. "Expression Of New Mutant Alleles Of AS1 And AS2 Genes Controlling Leaf Morphogenesis In Arabidopsis Thaliana." Russian Journal of Developmental Biology 39.1 (2008): 6-12. Web.