Background Information: In the nervous system, the brain processes information b
ID: 195307 • Letter: B
Question
Background Information: In the nervous system, the brain processes information by transmission of electrical and chemical signals through a network of neurons. These signals travel through synapses which connect two neurons. Neuroligins are cell-adhesion molecules that function to connect two neurons at synapses and mediate proper signalling across the synapse. Interestingly, neuroligin function has been linked to autism spectrum disorder (ASD) which is primarily manifested by delayed development and deficiency in social interaction and communication in patients. Mutations in genes encoding neuroligins have been identified in ASD patients. The molecular mechanism of how neuroligins function in ASD has been investigated using mouse models. The mouse gene NL3 encodes a neurolignin. Aberrant NL3 gene function in mice results in synaptic dysfunction and a diverse range of abnormal behavior including a subset that resembles ASD patients. A striking phenotype of NL3 mutant mice is increased repetitive behavior compared to wild type/normal mice. There are two alleles of the mouse NL3 gene. One allele (referred as "+" or wild type) produces NL3 protein which results in the synthesis of neuroligins for synaptic function. In contrast, the other allele (referred as "") does not produce any NL3 mRNA (and hence no NL3 protein) resulting in an inability to produce neuroligins.Explanation / Answer
Hi,
The gene NL3 can have mutations outside the coding region. These regions include promoter sequences, cis-acting upstream elements or RNA termination sequences. The mutations in promoter would affect the binding of RNA polymerase. If RNA polymerase cannot bind, then naturally no mRNA can be synthesized. Similarly if the cis-acting upstream elements are mutated, then the sigma factor cannot bind efficiently and recruit RNA polymerase.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.