How to determine a correct promotor sequence? (Bisulfite sequencing - uni assingment) aspiring bioinformatician here, I'd like to ask you for help with an university assignment. First let me post the entire question:
Design primers for bisulfite sequencing of the promoter of the ACE2 gene in microbat  Myotis lucifugus (based on the annotation of the Broad Institute Myoluc2.0/myoLuc2). The gene is localized on the contig GL429816. As a transcription start, use the start of the ACE2 transcript variant XM_023753670.1; once you find ACE2 in the UCSC genome browser .You will find it in NCBI RefSeq track 
I don't want anyone to solve it for me but I do have a problem with one aspect. I am not clear on how to determine what is a valid promotor for this gene in microbat. I do know it is the upstream sequence however I am not clear on how to tell the number of upstream bases that are the actual promotor. I did find some sources for the actual promotor sequence determined by much smarter people than myself however those are for ACE in humans so I am afraid that it is not applicable in my case.
Any help will be appreciated, even just pointing me in the right direction where I could find my answer would be enough. (And yes I tried contacting my teacher about this, but unfortunately he is not answering and the deadline is approaching rather quickly).
I think there is no fixed size. Ideally you would have something like histone ChIP-seq or ATAC-seq data to approximate the relevant upstream interval. Since this is not always possible most people go with -500bp. Others might have different suggestions though. Maybe matching known motifs of transcription factors that regulate that promoter to the upstream region can help approximating a better window. But as Sanger sequencing usually gives about 1kb of sequence I'd just take a 500bp to 1kb window and sequence that, fwd and rev primers for sequencing to have double confirmation.