The Scribal Art As Axis Mundi?

My underlying question in this post is how much of the context supporting one portion of a word’s semantic range is normally carried over into another context where the word has a somewhat different meaning. Note I am talking about one context of meaning being imposed, however slightly, on another context. If I say “Joe plays the piano” to what extent am also raising of the possibility that Joe might play football? When I use the word “play” to what extend am I drawing some relationship between making music and contact sports. Many punning jokes work by imposing of one linguistic context on another by way of a single word shared word.
Now for my real problem: In lines 12Sum and 12Akk of the bilingual treatise which Sjöberg called “In Praise of the Scribal Art” we read in Sumerian (12Sum) nam-dub-sar-ra dur-da-gan-KA-[x x] x nun me [x x x] which is rendered in Akkadian (12Akk) ṭupšarrūtu markas kulla[t x x] x i me [x x], “The scribal art is the bond of all of (markas kullat) [. . .].” It would be nice to know what was in the lacunae at the end of the lines. It is possible but only barely possible that the ME in both lines should be read “heaven,” šamê in Akkadian (see MLS 14 91:71:7; CAD Š1, 339). But the fuller Sumerian nun me is more likely part (or all) of some kind of professional designation. Perhaps here it stands for a sage, a priest or an exorcist, an apkallu, but several other options cannot be ruled out. Neither the traces of the Sumerian or the Akkadian lines reasonably support reading an-ki / šamê u erṣetim, “universe / heavens and earth,” in the lacunae, by the way, a reading I would very much like. Even so, Akkadian markasu (mundanely “rope”) often signifies a link, an axis mundi, between the heaven and the underworld or between heaven and earth (CAD M1 283, K 505). While the lacunose ends of both lines 12Sum and 12Akk cannot be reconstructed in this way, the learned author of “In Praise of the Scribal Art” was certainly conscious at some level of the full semantic range of markasu.
My guess is that line 12 of “In Praise of the Scribal Art” should be understood as saying that the scribal art is the bond, the markasu, that binds together all the other professions. But who knows?
References:

Hurowitz, V. A., “Literary Observations on ‘In Praise of the Scribal Art’,” JANES, 27 (2000), 49-56.
Sjöberg, Å W., “In Praise of the Scribal Art,” JCS, 24 (1972), 126-131.